HVAC Mode Door [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: HVAC Mode Door


potts200
07-06-2006, 10:12 AM
I knew this day would come I just hoped it wouldn't be in July in NW Florida. I think the HVAC mode door actuator has finally failed in my '02 Trailblazer LTZ. I can cycle the vent modes on the automatic climate control but the vents on the dash don't blow air anymore. I can only get air out of the defrost vents below the windshield or out of the floor vents. While it is been 100 degrees outside this week my feet have been nice and cold while driving.:rolleyes: I can't find any posts of owners having this problem fixed; has anyone had it replaced by the dealer or replaced it themselves and if so can you share your experience and findings? I've gotten a few quotes from around the area and they run from $450 to $550. The part is $50 and the rest of the bill is 4.9 hours of labor. Does this seem like the right price range considering there is a new tool to avoid disassembling the dash? Unfortunately I don't have any idea where under the dash this door is or what the procedure is to replace it. I am resigned to having the dealer repair but I want to be sure I take it to a shop that is using the most updated and least invasive procedure.

lars02Voy
07-06-2006, 02:39 PM
I'm having nearly the same problem. And I'm in SE Florida. I feel your pain man! I tired looking under there.....I'm gonna tear the dash apart anyway.

the roadie
07-06-2006, 04:22 PM
I knew this day would come I just hoped it wouldn't be in July in NW Florida. I think the HVAC mode door actuator has finally failed in my '02 Trailblazer LTZ. I can cycle the vent modes on the automatic climate control but the vents on the dash don't blow air anymore. I can only get air out of the defrost vents below the windshield or out of the floor vents.
If your mode actuator moves the door at all, then it might not be totally dead yet, but there's a tiny chance it needs to calibrate itself for min and max positions. Without a dealer scan tool, you can do it yourself by turning the car off, removing the HVAC-B fuse for ten seconds, installing the fuse, starting the car and don't touch the HVAC controls for 40 seconds.

As always, a failure like this could have set some DTC codes, and if you have a code reader or borrow one from Autozone, anybody like me with a factory manual could look 'em up and home in on the root cause.

the roadie
07-06-2006, 04:28 PM
I'm having nearly the same problem. And I'm in SE Florida. I feel your pain man! I tired looking under there.....I'm gonna tear the dash apart anyway.
Ummm, without a manual, and a plan, about the best you would do is find a loose connector. But a bad connection would have set a DTC code, so I would recommend borrowing a code reader first. Or spend the $50-100 on Ebay to buy an Actron. Heck, a blown diagnosis or doing additional damage will waste more than $100 anyway. I can't see buying a modern high-tech vehicle and NOT owning a code reader for it.

tblazed
07-06-2006, 06:24 PM
I've gotten a few quotes from around the area and they run from $450 to $550. The part is $50 and the rest of the bill is 4.9 hours of labor. Does this seem like the right price range considering there is a new tool to avoid disassembling the dash?

In a word, no. Comes out to about $900 an hour based on the labor rate.

The bulletin regarding the new tool 05-01-38-001A (04/08/2005) says .6 hrs to replace the actuator.

"D1808 Actuator And/Or Motor, Electric-Mode Valve-Replace 0.6 hr"

I wonder what they were going to do for the other 4 hrs!

Bulletin also says about the old rate before the shortcut and tool came out in late 2004-early 2005...

"Do Not Use This Labor Operation D1829
Cam And/Or Cam Actuator Lever, Mode Control-Replace 3.2 hr"

I know at least one person who got the done job free when the service manager was confronted with this info. and was embarrassed about such a blatant overcharge. Good Luck!

potts200
07-06-2006, 10:42 PM
Oh, that news makes me giddy.:p It was pretty disheartening to get aproximately the same quote from three local dealers. tblazed, do you have the full text of the TSB that you could pm to me or can you direct me to a website that has the full text? Do you think a dealer would show me the TSB if I asked for it by number? Either way it'll have to wait until next week. I don't want to confront a service manager on a Friday afternoon. Thanks for the tips!:) I will try the HVAC reset just in case but something has definitely gone wrong with the system.

Crossroader
07-07-2006, 12:27 AM
tblazed, do you have the full text of the TSB that you could pm to me or can you direct me to a website that has the full text?

I am also interested in obtaining that TSB. I've seen it, but I can't remember where I saw it....

Thanks.

potts200
07-21-2006, 11:52 PM
Armed with the TSB for the door mode actuator replacement with the new tool I had 02 LTZ fixed! I was able to get a service manager to take a look at the TSB and he stated he had never heard of the tool but investigated regardless. Turns out they had the tool at the dealer. Of course we both realized that if any other part was broke besides the actuator then the dash may have come out anyway. BUT, I got lucky and they were able to replace the actuator without tearing out the dash. :) The total bill was around $157 after parts and labor but that is much better than the $450 to $550 I was orignially quoted. Trailvoy and it's members really helped out and is a wonderful asset to have. Can't touch the power of the collective! Now it's time to work on those endlinks:rolleyes:

tblazed
07-22-2006, 10:52 AM
Full text of the bulletin...

Subject: Info - Essential Tool for HVAC Mode Door Actuator Replacement
#05-01-38-001A - (04/08/2005)

Models: 2002 Chevrolet TrailBlazer Models

2002 GMC Envoy Models

2002 Oldsmobile Bravada

--------------------------------------------------------------------------------

This bulletin is being revised to update the references to the service
procedures in SI and add warranty and parts information. Please discard
Corporate Bulletin Number 05-01-38-001 (Section 01 -- HVAC).


--------------------------------------------------------------------------------

The purpose of this service bulletin is to announce the release of a new
essential tool to service the Heating, Ventilation and Air Conditioning
(HVAC) Mode Door Actuator. The new tool is an HVAC Puller, special tool
number GE-47676, which was shipped in the Fall of 2004 to all Chevrolet and
GMC dealers. It will no longer be necessary to replace the entire Mode Door
Cam Assembly when only the Mode Door Actuator requires replacement. Previous
to the release of this tool, it was necessary to remove the entire
Instrument Panel Carrier to replace the Mode Door Cam Assembly. Now the Mode
Door Actuator can be serviced from underneath the left side of the
Instrument Panel Carrier using this new special tool.

The service procedures in SI have been updated to include the use of this
new special tool. To replace the entire Mode Door Cam Assembly refer to the
Mode Cam Replacement procedure in SI for more information (Document ID
#1618104). To replace just the Mode Door Actuator, refer to the Mode
Actuator Replacement procedure in SI for more information (Document ID
#1609154). The labor time associated with labor operation D1808 has been
changed to reflect the time savings when this new special tool is used.
Labor operation D1829 has been added to the labor time guide to be used if
the entire Mode Door Cam Assembly is replaced.

Parts Information
Use This Part Number
89018539
Actuator ASM, Mode Valve

Do Not Use This Part Number
89018525
Cam ASM, Mode Valve


Use This Labor Operation
D1808*
Actuator And/Or Motor, Electric-Mode Valve-Replace
0.6 hr

Do Not Use This Labor Operation
D1829
Cam And/Or Cam Actuator Lever, Mode Control-Replace
3.2 hr

*This time is updated from the current Labor Time Guide. The next update of
the Labor Time Guide will contain this change.

havoc
10-09-2006, 11:34 PM
Hvac Door monster struck me too. 1 Day after I install my HID lights.

Its not the first time it's been "stuck" but this time its not doing anyhing regardless what mode I put it in.

I tried the "pull the fuse out and wait" trick and no luck. Any other suggestions before it goes to the dealer?

Jman423
10-13-2006, 09:13 PM
After I experienced an accidental short that blew the fusable link (in the fuse box under the hood), I was having trouble with the A/C... The A/C worked from the windshield defroster, and a mix of the defroster and the floor, but no dash vents. I tried everything that was mentioned in terms of callibration with no luck, so I took it to the dealer this morning and they took care of it.

It turned out to be the acuator that switches the air flow (tucked way behind the dash). I am assuming that the short caused this acuator to fail, so when I finally got the new fusable link, the acuator was still bad.

The bill was $540 when all was said and done, so let me say how ecstatic I am to have a great extended warranty with no deductable. The labor was like $485 and the part was like $57.

The funny thing is that the truck was only there for three hours total, the billed labor was 5.1 hours :undecided Obviously, they had this new fangled tool that allows them to replace this actuator without acutally ripping apart the dash board, but they claimed to the warranty company that they did rip the dash out.

Anyway, all is good now. If you find yourself needing this done and you don't have the warranty, please take the time to print the TSB that tblazed mentioned in this thread, it could save you hundreds of dollars :m2:

havoc
10-23-2006, 02:08 AM
FYI the bulletin only applies to the 2002. I had them research if there was a similar part for my 2004 Xuv and no luck.

Dealer fixed it and I had it 2 days later. Good thing they gave me a Tahoe for a rental...

MTPockets
10-23-2006, 11:47 AM
FYI the bulletin only applies to the 2002. I had them research if there was a similar part for my 2004 Xuv and no luck....

Is the HVAC system different on 2003+? Can anyone confirm? I bet the hardware is all the same.

Joel

autotech
10-24-2006, 10:20 PM
that particular actuator was only used on 2002. it was changed for 2003 and up.

APDMC6008
11-03-2006, 12:27 PM
Mine failed once about two years ago, and it's failing again. The dealer also broke the two brackets that are part of the dash frame that hold the drivers side knee bolster in. :mad: I noticed it a year later, and it's too late to have them repair it. I have lots of aftermarket wiring installed for the warning lights, etc, so they'd prolly blame it on me. I'm hoping I do not have to have it all done again. :(

tasnat23
12-06-2006, 03:17 PM
does anybody have a diagram of where this mode door actuator thing is?? :)

i bought a haynes manual today and it didnt tell me squat. and i also tried the reset thing that the roadie reccomended, but that didnt work either....

anybody have suggestions...... i would like to do this project myself..... not really wanting to pay someone 600 bucks to do something that i can do myself....

PowderKeg
12-07-2006, 02:07 AM
When this starts to fail do you hear a ticking noice from up under by the steering wheel. I hear a ticking from now and then sometimes never stops. It seems to be something with the HVAC since I can change the ticking by changing the settings cooler or hotter...Thanks

tasnat23
01-02-2007, 09:33 PM
anybody have an answer for me???? :( i keep trying to search the internet and i still cant find any type of diagram

kings21
01-19-2007, 04:25 PM
the ticking just started on my 02 TB - of course the Value Guard doesnt cover it - Dealer claims about 7 hours labor!!! what a joke - I'll bring them the TSB, but I'd also like to know how to get at this thing myself - if anyone has pics, please post!

1TrueSS
01-22-2007, 03:44 PM
I am having this probrm too, but in my 03 Envoy. I am throwing codes B0263 "Air Flow Control 6 A/C Circuit" & B3770 "Air Flow Control 6 (A/C) Feedback Circuit" I can't clear the codes either?! I can hear the motor moving, just not when I put it on the top vents only?!

tasnat23
04-18-2007, 03:05 PM
well i went to the dealer to get mine fixed finally... they told me it would take 3 hrs, even with the TSB...

so i bought the part. me not knowing much about installing this part, it took me ONE HOUR!!!! how ridiculous!!!! so it cost me 55 bucks, for the part. so if any of you need a how-to to install this part... give me a holler... ill let you know...

all you need is a 9/32 socket, and a 7/32 socket. take off the lower panels on the driver side....take out the left floor vent tube, and look straight up. easy as that. you dont even have to be a contorsionist to get it out

hope this helps some of you, also the part number is
ACD# 15-73596 GM#89018675

1TrueSS
04-18-2007, 04:33 PM
I got my fixed at the dealer back in Feb. Now I have another ploblem!? All the vents work, but sometimes when the heat is on I get cold air out of the drivers side only. When I turn the fan on high just the drivers side blows and it is still cold when the heat is on. This only happens every now and then and when it does it lasts for about two days.

TrailBlazzin
05-11-2007, 08:49 PM
well mine doesn't work either, where is the "how to" on this......

is this the part i need for auto hvac controls??

ACDELCO Part # 1573598 {#89018676}
ACTUATOR,DEFR VLV w/A/C FRT AUTO/AUX CONT(CJ2) or A/C FRT MAN/AUX CONTROL(CJ3)

TrailBlazzin
05-14-2007, 03:21 PM
well i crawled under the dash today and can't figure out wich one i am trying to replace... i don't have the new part yet to figure it out so i was just going to remove it for now until i get it.... can someone name the 3 parts in this diagram???

http://i132.photobucket.com/albums/q36/trailblazzin/105678020.gif

PROSPHOTO
05-14-2007, 03:32 PM
well i crawled under the dash today and can't figure out wich one i am trying to replace... i don't have the new part yet to figure it out so i was just going to remove it for now until i get it.... can someone name the 3 parts in this diagram???

http://i132.photobucket.com/albums/q36/trailblazzin/105678020.gif

(1) Air Temperature Actuator-Left
(2) Defrost Actuator
(3) Mode Actuator

TrailBlazzin
05-14-2007, 03:32 PM
thanks

TrailBlazzin
05-14-2007, 04:10 PM
so is this the correct one?? doesn't look the same as the one in the diagram but it was in that location....

also i popped it apart to look inside and is pretty much set up like a servo, i used a battery and hooked it up to the motor to my suprise it worked little slower in one direction.... do you think this is the problem still???

http://i132.photobucket.com/albums/q36/trailblazzin/Photo0030.jpg

siggy69
06-09-2007, 02:43 PM
i have a 2003 gmc envoy the problem is my driver side blows hot and colld air like it should but my passenger side only blows hot air no cold air at all what ccould it be and what can i try to fix my self i dodnt trust the local gmc dealer in my area

918designs
07-02-2007, 02:06 PM
I have a 2004 TB and I have the same problem with the upper vents not blowing, I would like to know how to replace it but cannot contact anyone on here because I am a new member. I noticed that 2 part numbers have been listed for the actuator, one is 89018539, the other is 89018675. Im not sure which one would be the correct one to order. If someone could let me know which one would work on the 04 I would appreciate it.

918designs
07-02-2007, 02:07 PM
tasnat23, I dont know if you will see this post anytime soon but I would like to have some more info on how to replace the part. If you could email me at dustin_918@yahoo.com I would appreciate it. Thanks

Nick the Marine
08-29-2007, 05:15 PM
I was able to use the 2002 model year TSB (050138001A Essential tool HVAC Mode Door Actuator Replacement) to get my 2004 GMC Envoy fixed. The tool enables the actuator to be replaced without removing the dash/instument cluster on 2002 and newer TB/ENV's. All in all it saved me $450.

Thanks for all the members that responded to this thread for the information!

S/F!

Nick

PROSPHOTO
11-13-2007, 02:41 PM
TrailBlazzin; do you still have the picture that you posted of the actuator? Can you re-post it?

:thx

culzero
11-13-2007, 09:19 PM
Well i replaced the HVAC Mode Door but it still doesn't work. Any advice?

neelskit
11-14-2007, 04:22 PM
Try the reset procedure shown here:

http://forums.trailvoy.com/showpost.php?p=139608&postcount=3

sw2001
02-01-2008, 03:23 PM
Can anyone tell me the correct part number to replace mine in my 2002 LTZ? Also, does anyone have written instructions, pictures or diagrams that I could use to replace this myself? Any help would be much appreciated.

AbsoluteZero
02-01-2008, 06:44 PM
I am having this probrm too, but in my 03 Envoy. I am throwing codes B0263 "Air Flow Control 6 A/C Circuit" & B3770 "Air Flow Control 6 (A/C) Feedback Circuit" I can't clear the codes either?! I can hear the motor moving, just not when I put it on the top vents only?!

I had the issue of no upper level airflow. Repair order showed mode actuator p/n 25790869 and B0263. Was covered by extended warranty about a year ago and 48K miles.
Curious what scanner you used. Mine only reads powertrain codes.

kamdog211
03-13-2008, 08:56 PM
I was having the same issue with my 03 Envoy with manual HVAC controls. Air only blew out of the defrost and floor vents no matter how what setting I put it on.

I tried the reset process with no results. I did notice this, when I removed the HVAC b fuse and turned on the fan, it would cycle through the dash vents for about 5 seconds then blow out of the defrost and floor vents.

I was able to fix this be replacing the mode door acuator.

ACDelco part # 15-73596
GM # 89018657
cost was $37 from a parts store

It was a pain to replace it but. Fist you have to take the bottom cover from under the dash on the drivers side. I also removed the plastic floor air channel. If you get on your back and look up, it will be to your left. There are two acuators and the look almost alike. You want the one that is to the right. It took about 1 hour to do and like I said, sort of a pain, but well worth the $450 I saved.

Hope this helps someone.

gdewit79
03-14-2008, 04:33 PM
You did not happen to take pictures, did you? I am having similar problems with mine, and I do not want to order the actuator from GM unless I know which one it is. The last time I was there, they were listing two actuators, and the guy behind the counter was of little or no help to me, especially after he told me he had never heard of the problem before!!

kamdog211
03-17-2008, 08:47 AM
Sorry, don't have any pics of it, not sure where I put the old part. There are two acuators that are beside each other, one does not have a gear, and the one I used had a white gear piece on it. I had a hard time finding it also, so what I did was went to the ACDelco site and looked up the part # then found shops that sold it. Hope this helps. Let me know if you have other questions.

I'd be happy to help other members since this site has helped me so much.

rob d
05-02-2009, 09:37 PM
I just changed the motor due to no air comming from the dash vents. This was not too bad for the average size guy,you do have to twist yourself around a little bit. The motor your looking for is located under the drivers side dash renove the lower panel that holds obd port and large wire harness ,you will need a small screwdriver to remove this .Next pull panel down and away you will see a piece of duct one press tab holds it in place,just pull down,next pull lower part of dash off you will find the motor behind the stereo.There are two motors, you want the higher one.Put the dsh selector knob to defrost only unhook wire from motor,remoove two screws and pull off motor note position of white cam,when you get the new part you will have to plug the harness in so the new cam is the same.Installation is the reverse.This may sound verry overwhellming,if you pay attention and are patient it will take about an hour.I also found out the part number on the motor is a casting number so dont be alarmed if you think it is the wrong part, check with your local dealer. (GOOD LUCK)

jscott70
05-29-2009, 07:56 PM
Would this also apply to the 2005 model? Dealer said they had to take the dash apart. $700 quote was given. Advanced Auto Parts had the part at $153.00.


Thanks,

the roadie
05-29-2009, 08:39 PM
Yeah. They LOVE to take the dash apart. Owners can be careful and do the same job with just a lot of cursing, finger pinching, and beer. Much less than $700 worth of beer.

mxracer46x
05-31-2009, 04:46 PM
I have a 2003 trailblazer and had same problem with no air coming from dash vents. I tried the fuse trick with no luck. I'm a little short on cash and cant afford the new mode door acuator from dealer $97. I decided to try to open door myself so i could have cold air out of the dash vents.

After you take off panels and plastic floor vent duct pipe look up and find the correct mode door acuator. Look on the side with the sticker that has letters H,L and some numbers on it. In the center of part you will see a round hole with a metal piece that has two notches. Find something that fits in the notches of that hole, like a screwdriver. I didn't have a screwdriver that size so i used an old flat nosed butter knife that fit almost perfect. You might need to modify something to fit if you don't have anything. Stick your tool in hole and turn about a quarter turn. It was a little difficult to turn but you will feel and hear the mode door open. Next unplug the wire harness that goes to that acuator. I put black tape over end of wire harness just to be on the safe side. Reinstall your plastic floor duct vent and panels. This took me about 10-15 minutes to do.

I did try to leave the wire harness plugged in but when i restarted vehicle the door closed. The dash vents will blow now all the time unless you turn off blower fan or turn off dash vents on the dash where the air deflector is.

I'm not a auto mechanic and do not know if what i did will cause any problems to my vehicle or yours if you try this. I was at a point of go without dash vents or pay for a new part, so i figured i had nothing to lose if i did break the mode door acuator. just be sure you are trying to open the correct one. So far i have not had any problems and don't think i will. Try at your own risk.

Good Luck and Thank You to all who have posted here with problems and solutions that have helped me out with my trailblazer

Roamingdoc
07-06-2009, 03:36 PM
HI all,
TrailVoy is an AMAZING group of people, thank you.

I recently installed a PCMforLess PCM on my wife's '02 TB... 4whldrv, lots of bells and whistles ( I 'did' say Wife, right?) and after reconnecting the battery, the driver side vents no longer responded to any changes in mode (a light, low 'breeze' of hot air only - no matter the temp selection or even heat vs A/C made any difference at all - the Pass side works; A/C, temp, top or bottom or mixed, etc... that side works). Basically we've shut drv side off with on/off wheels (we have the dual mode thingy - right, wife..)

Roadie and some others suggested the 'HVAC-B' fuse trick, no joy... I'd also tried the battery trick (disconnect, believe it was 30 minutes, reconnect, no touch nada and turn key to 'run' but not 'start' for 90 seconds or more to reset), well, still no joy.

So now I am figuring that I need to either replace the Actuator door mode thingy (what "is" the real name for this?? Do I have it right) by removing the driver side lower dash panels and then locating the 'Actuator' motor and replacing it with one bought on ... ?? Ebay ?? RockAuto ?? GMforLess ?? anyway... I noted RODIE supplied a 'new' notice from Chevy that they can now repair the whole deal with a new tool for the '02 for (perhaps?) less than $200? Says it should be about .6 hrs of labor?? 'Dat' be true?

BTW, the PCMforLess change was / is REMARKABLE... I haven't calculated the savings on a recent 3000 mile road trip, but we got a solid 2.5 mpg increase across the boards! Really... and shifting, acceleration, all aspects of the engine/trans and driving WERE markedly improved. A good CHOICE 'even' if this unfortunate Actuator issue came up! :woot:

Just wanted to bring this issue back up and get a few questions answered.
Thanks.
Doc

kamdog211
07-06-2009, 04:14 PM
I had to do this repair about a year ago. The part numbers are listed below.

ACDelco part # 15-73596
GM # 89018657
cost was $37 from a parts store

The install itself is a pain but does not require special tools (at least on my 03 Envoy). I looked up the ACDelco part # and called around the parts stores. I called the dealer and they told me it would cost me a little over $150 for the part if I can remember correctly. I was able to find it at a parts store locally for $37. I can't remember the name of the store but it was not autozone, advance or pep boys. What I did was I called ACDelco and they were able to give me a list of ACDelco parts suppliers around me and I contacted each one until I found the part.

A quick google found this link.

http://www.fixya.com/cars/t796937-no_air_flow

Hope this is some help for you.

the roadie
07-06-2009, 04:19 PM
There's another thread you should search for where a member made his own tool. Some folks do it without a puller tool. But yes, you need the mode actuator.

******************************************

Roamingdoc
07-06-2009, 04:30 PM
I have read thru most (if not all, whew!) of the 'vent', 'air vent', 'blower', 'hvac', based threads.

Most of the comments are very helpful but ONE issue seems to raise its head often: Are we dealing with the 'drvs temp actuators' or the 'vent floor-dash actuators'?

As I wondered earlier, I get air top and bottom and mixed, heated and A/C from the passenger side controls (dual controls) but nothing on the driver side. I do get 'defrost' (which I understand is a separate controller) equally from both and HOT as well...

So (Roadie and the others who have busted their butts in helping us less savvy TB and EV drivers) "what" would be the biggest individual "indicator" of one or the other issue? Is there a way to correlate the symptoms, step by step, to the 'real trouble'?

I'm going to take off the lower dash and "observe" the "door actuator" on the driver side and see if it appears jammed... I am assuming (ahhh) that if it moves correctly, then I've got a 'heater [or is it a temp] actuator' issue?

Thanks.
Doc

the roadie
07-06-2009, 04:45 PM
...Are we dealing with the 'drvs temp actuators' or the 'vent floor-dash actuators'?.Both have had failures reported. Rarely one of the other three.

Diagnosing it is about as trivial as it can be, as long as you understand the inner working of the plenum (as hinted at by the lack of a PASSENGER SIDE MODE actuator).

There is only ONE mode actuator. If there's any passenger side airflow to the feet area at any temperature, the SAME amount of airflow should show up at the driver's side feet. If the passenger dash vents blow when you put the mode to send air to the dash vents, then the driver's vents will have the same airflow. They HAVE to.

See? Simple.

Not to say that you couldn't have TWO actuator failures, but it's very easy to diagnose when you take the panels off.

Roamingdoc
07-06-2009, 04:56 PM
Well, off it will come... found the '02 homemade tool, very cool...
http://forums.trailvoy.com/showthread.php?t=59212&highlight=Homemade

But, as an afterthought... 'if' the passenger side "is" working, hot, cold, dash and floor, then the Floor/Dash
Vent Mode Actuator would seem to be functioning. "If" there is only 'one' of them, are you making the point that the real issue for my situation (no change in temp and no rush of air at floor or dash no matter the 'speed' of fan or temp selected) is really the 'drivers temp actuator'? Or shall I have a few more beers?

I'll take photos as we do it... several... so forth. Later this week, we are hoping.

the roadie
07-06-2009, 05:43 PM
...no change in temp This has to be the driver's side temp actuator.

and no rush of air at floor or dash no matter the 'speed' of fan or temp selectedI can't explain this. You get DIFFERENT airflows out of the left and right sides, and the driver's side doesn't change no matter which mode you're in?

Maybe you have a mouse nest or somebody shoved a pair of underwear into your plenum, and your driver's airflow is jammed.

Sure you have the vents open, and not in the blocked-off condition? Does the footwell airflow change speed when you change modes?

Roamingdoc
07-06-2009, 07:40 PM
No mouse nests... car is well maintained.

Since the one disconnect of the battery (and then thru all the 'attempts' at resetting the HVAC system - disconnect batt., follow time requirements, etc) the 'drivers' side gets a very slight 'breeze' of air (this is 'even' if all is off, or we've put mode on 'dash' only, floor only, all other mixes) out of the "dash" vents. It is always warm and heats up with the engine... until it seems very warm. We can use the 'vent' adjusting wheels to 'stop' it and that pretty much disallows any air from coming out the driver's side "dash vents"... the PASS. side works well, 'dash' vents blow outside air if A/C is off... blows A/C when on, we can change the PASS side 'mode' to floor or dash or mixed and it is good.

All the issue(s) are around the 'temperature' and 'amount' of air coming from the Driver's side 'dash'... we seem to get a tiny (very small amount) of 'hot' air coming from the Driver's side 'floor' vent WHEN we shift mode to floor but no change in volume of air or temperature... stays a slight breeze and warm to hot depending on how long the car has been running.

That is why I've read and re-read all the commentaries BECAUSE my circumstances don't seem to be "exactly" similar. I will pull the lower dash and see if I can find something that makes it obvious.

"IS" there a 'fuse' that runs the 'drivers temp actuator' solely by itself? Or is there a way to 'isolate' it as the cause (or not)?

Talked to Chevy... the Pasadena, CA 'Team Chevrolet' desires $101.00 to diagnose it... :bonk:

Many thanks.

RFuse2
10-21-2009, 11:09 AM
Hey Doc ... Have you figured out what was causing the issues with your HVAC yet?

Russ

Roamingdoc
10-21-2009, 11:16 AM
I wish I could say that I had... we've lived with it for this period and I have had some 'medical' issues interfere with fixing the dang thing... heck, I just added water to the battery. What a cluster that set up is (at least in the '02)... three bolts, still have to bend the 'cover' off to access the fill holes. Jeez. :weird:

I plan to fix it but right now cannot say exactly when. I hope to take pics when done.

As I mentioned, the 'passenger' side gets 'cold and hot' and we CAN alter the flow from 'dash' to 'floor', etc... so as there is only ONE control for 'dash' or 'floor' flow we are assuming this is the driver's side 'control' for hot or cold, etc... it just blows hot on the driver's side.
It appears to be an easier access to that control.
Doc

SuperSportUV
12-08-2009, 10:42 PM
Ok, so looks like from what I have read 'the new part' cuts the labur time from 4 hours down to 0.6hr for replacing the mode door actuator on a 2002/2003.

The only thing that I can NOT find is what changed in 2005 because my dealer says that in 2005 they changed something and also because my 2006 has power adjustable pedals that that will take longer and therefore its a 4 hour job...

Has anyone had this mode door actuator changed on a 2006 or newer?

slimtv
12-30-2009, 12:18 AM
If your mode actuator moves the door at all, then it might not be totally dead yet, but there's a tiny chance it needs to calibrate itself for min and max positions. Without a dealer scan tool, you can do it yourself by turning the car off, removing the HVAC-B fuse for ten seconds, installing the fuse, starting the car and don't touch the HVAC controls for 40 seconds.

As always, a failure like this could have set some DTC codes, and if you have a code reader or borrow one from Autozone, anybody like me with a factory manual could look 'em up and home in on the root cause.

Hello,

This site was a great find while in search of help for the mode door accuator clicking problem. I tried the above scenario but the air will still not blow out of the middle vents. It just blows out of the bottom when middle is selected. The clicking has stopped though. I still do have defrost air when selected(it used to click when selected).
How should I proceed? Have the dealer replace the accuator? That is what prompted the search of the web in the first place as my dealer wanted $867 for repair before I found this site. Thanks for the help.

SuperSportUV
12-30-2009, 01:03 PM
Hello,

This site was a great find while in search of help for the mode door accuator clicking problem. I tried the above scenario but the air will still not blow out of the middle vents. It just blows out of the bottom when middle is selected. The clicking has stopped though. I still do have defrost air when selected(it used to click when selected).
How should I proceed? Have the dealer replace the accuator? That is what prompted the search of the web in the first place as my dealer wanted $867 for repair before I found this site. Thanks for the help.



I just had mine fixed. Mine was doing 100% same issue.
You have a stripped plastic gear in the mode door actuator (thats what was clicking). It can be taken out, disassembled and rotate the gear 180 degrees (to use the good side), but for the labour its far better to spend the $60 on a new one and just replace it.

In 2002 model year the mode door actuator part was actually attached (pressed onto) the mode door actuator valve. The valve is the actual 'door flap' that moves the air to what mode you select (defrost, floor, vents..).
So in early 2002 the entire dash had to be dissembled to take the mode door actuator & valve out as a whole piece. Later on GM came out with a tool to detach the actuator from the valve and by doing this the dash does not need to be taken apart because now the mode door actuator can be uninstalled from under the dash (almost behind the stereo, above the gas pedal). This tool reduces the “warranty labour time” from 4.1hrs down to 0.6 hrs!
Warranty time is not generous, so they will want to charge more.
If you have power adjustable pedals, the labor time rises again to at least 4 hours (as I had to pay for on my 2006).

The 2 Part #’s are different for different years of these trucks. I ordered the wrong one and therefore I need to sell it. I believe it’s the one you are looking for: GM part # 89018539. If you have a 2006 or newer then you will need part # 89018675.
I will take $35 for it, it is brand new never used or installed. –AC Delco.

the roadie
12-30-2009, 02:05 PM
And you can fabricate your own tool if you're handy.

http://forums.trailvoy.com/showthread.php?t=65280 (pictures have gone missing because the host domain went away. I emailed the poster to see what's up).

http://forums.trailvoy.com/showthread.php?t=59212

twins
01-11-2010, 05:13 PM
Hi roadie,
can you tell me step by step how to take out the mode actuator because my front vent and lower is not working and may be can post some pictures to how to do it,I will very much appreciate it. thank you so much

the roadie
01-11-2010, 09:01 PM
can you tell me step by step how to take out the mode actuator because my front vent and lower is not working and may be can post some pictures to how to do it,First you get out your credit card and log into Paypal and send me $50 ...... :eek:

Just kidding! I did this once, but was in a big fat hurry and didn't take pics of the entire process. You should be able to figure it out from: http://forums.trailvoy.com/showthread.php?t=40235 if you ran a search for free. ;)

KNBlazer
01-14-2010, 06:05 AM
that tool only applies to 2002 models... right?

for 2004 Trailblazer EXT LS I need part number
89018675


to fix the No Air In Front Vents

I also disconnected the battery and the result was this...

chevy_girl
08-14-2010, 03:54 PM
I have been having the same problem and after doing some research found the problem. I have been putting off replaceing the mode actuator for the fact I didn't have anyone to do it for me and i have no clue where to start. I finaly order the part on ebay, got it this morning now i'm determined to get this thing fixed. I remimber someone saying something about the B fuse so I thought I would look some more to see what I'm really supose to do. After seeing this thread, I now have a new $50 part in my living room and ac that will blow from where ever i tell it after a 2 min job. Now I feel dumb.:duh:

Copasta
04-07-2012, 03:56 PM
Ok, I've just spent an hour or so reading over all the posts in this thread about the ominous "mode door actuator" / no air from vents problem that seems to plague TB/Envoy owners!

My problem is this: I have a 2003 Trailblazer with the same problem, except it's not the front vents, but rather the REAR roof vents that don't blow any air (hot or cold)! Does anyone know the part number to the door actuator that I need to replace for the REAR A/C to blow through the roof vents?

Any help in this matter will be greatly appreciated! I have been living without the rear air for about 2.5 years now! Time to fix it! Thanks!

SuperSportUV
04-07-2012, 08:45 PM
Ok, I've just spent an hour or so reading over all the posts in this thread about the ominous "mode door actuator" / no air from vents problem that seems to plague TB/Envoy owners!

My problem is this: I have a 2003 Trailblazer with the same problem, except it's not the front vents, but rather the REAR roof vents that don't blow any air (hot or cold)! Does anyone know the part number to the door actuator that I need to replace for the REAR A/C to blow through the roof vents?

Any help in this matter will be greatly appreciated! I have been living without the rear air for about 2.5 years now! Time to fix it! Thanks!


Hey there,
I assume it must be the same sort of function or servo that moves the air to different locations…
I have 2 hvac mode door actuators that look the same but are different part #'s, they have been sitting on my desk (buried under paperwork for the past few years). I bought them but they are not for my particular 2006 Trailblazer SS and the store would not take it back because its "electronics"...
Anyway, if you find out that one of these that i have is the one you need let me know!
for sale;
1) made by woory
part #'s
HL 52402610
010052902A

2) Made by CEI
Part #'s
MT 52408412
3243371B

Bushman15
04-21-2012, 01:03 AM
No mouse nests... car is well maintained.

Since the one disconnect of the battery (and then thru all the 'attempts' at resetting the HVAC system - disconnect batt., follow time requirements, etc) the 'drivers' side gets a very slight 'breeze' of air (this is 'even' if all is off, or we've put mode on 'dash' only, floor only, all other mixes) out of the "dash" vents. It is always warm and heats up with the engine... until it seems very warm. We can use the 'vent' adjusting wheels to 'stop' it and that pretty much disallows any air from coming out the driver's side "dash vents"... the PASS. side works well, 'dash' vents blow outside air if A/C is off... blows A/C when on, we can change the PASS side 'mode' to floor or dash or mixed and it is good.

All the issue(s) are around the 'temperature' and 'amount' of air coming from the Driver's side 'dash'... we seem to get a tiny (very small amount) of 'hot' air coming from the Driver's side 'floor' vent WHEN we shift mode to floor but no change in volume of air or temperature... stays a slight breeze and warm to hot depending on how long the car has been running.

That is why I've read and re-read all the commentaries BECAUSE my circumstances don't seem to be "exactly" similar. I will pull the lower dash and see if I can find something that makes it obvious.

"IS" there a 'fuse' that runs the 'drivers temp actuator' solely by itself? Or is there a way to 'isolate' it as the cause (or not)?



These are my symptoms to a "T" but they exist on my 08 Envoy Denali. Anyone come up with a logical expanation to this odd case?

Thanks for your input

TJSDENALLI
04-22-2012, 11:00 PM
:offtopic::bonk:Full text of the bulletin...

Subject: Info - Essential Tool for HVAC Mode Door Actuator Replacement
#05-01-38-001A - (04/08/2005)

Models: 2002 Chevrolet TrailBlazer Models

2002 GMC Envoy Models

2002 Oldsmobile Bravada

--------------------------------------------------------------------------------

This bulletin is being revised to update the references to the service
procedures in SI and add warranty and parts information. Please discard
Corporate Bulletin Number 05-01-38-001 (Section 01 -- HVAC).


--------------------------------------------------------------------------------

The purpose of this service bulletin is to announce the release of a new
essential tool to service the Heating, Ventilation and Air Conditioning
(HVAC) Mode Door Actuator. The new tool is an HVAC Puller, special tool
number GE-47676, which was shipped in the Fall of 2004 to all Chevrolet and
GMC dealers. It will no longer be necessary to replace the entire Mode Door
Cam Assembly when only the Mode Door Actuator requires replacement. Previous
to the release of this tool, it was necessary to remove the entire
Instrument Panel Carrier to replace the Mode Door Cam Assembly. Now the Mode
Door Actuator can be serviced from underneath the left side of the
Instrument Panel Carrier using this new special tool.

The service procedures in SI have been updated to include the use of this
new special tool. To replace the entire Mode Door Cam Assembly refer to the
Mode Cam Replacement procedure in SI for more information (Document ID
#1618104). To replace just the Mode Door Actuator, refer to the Mode
Actuator Replacement procedure in SI for more information (Document ID
#1609154). The labor time associated with labor operation D1808 has been
changed to reflect the time savings when this new special tool is used.
Labor operation D1829 has been added to the labor time guide to be used if
the entire Mode Door Cam Assembly is replaced.

Parts Information
Use This Part Number
89018539
Actuator ASM, Mode Valve

Do Not Use This Part Number
89018525
Cam ASM, Mode Valve


Use This Labor Operation
D1808*
Actuator And/Or Motor, Electric-Mode Valve-Replace
0.6 hr

Do Not Use This Labor Operation
D1829
Cam And/Or Cam Actuator Lever, Mode Control-Replace
3.2 hr

*This time is updated from the current Labor Time Guide. The next update of
the Labor Time Guide will contain this change.

OK GUYS... IM NEW TO THIS BUT I HAVE A QUESTION REGARDING MY REAR AIRBAGS ON MY 2006 ENVOY DENALI. A WEEK AGO EVERYTIME I CRANKED MY TRUCK I WOULD HERE THE COMPRESSOR COME ON TO LEVEL THE TRUCK THEN CUT OFF. OVER THE LAST COUPLE DAYS I HAVNT HEARD IT CUT ON AND THE TRUCK ISNT SAGGING. I HOOKED IP MY LAWN TRAILER TO IT AND AS THE REAR BEGAN TO SQUAT, THE COMPRESSOR DID NOT COME ON TO LEVEL IT. I HAVE CHECKED THE FUSE AND EVEN MANUALLY TURNED IT ON BY THE INFLATOR SWITCH IN THE CARGO AREA AND THE COMPRESSOR CAME ON. SO I CANT UNDERSTAND WHY ITS NOT COMING ON TO LEVEL THE TRUCK AUTOMATICALLY. I DONT WANT TO DO THE COIL SPRING CONVERSION BECAUSE I LIKE THIS FEATURE. IM AT A DEAD END! CAN ANYONE PLEASE GIVE SOME DIRECTION ON THIS OR SHARE SOME INSIGHT PLEASE? THANK YOU IN ADVANCE!!! NOT SURE HOW TO CHECK MY MESSAGES ON THIS SITE YET SO COULD YOU PLEASE EMAIL ME AT tjambrose79@yahoo.com.. until i can figure out how to check my messages on this site?

Bushman15
04-27-2012, 04:48 PM
Well I got up under the dash and found all three of the actuators. Pulled the fuse for a reset. Turned on the key and saw the top two actuators moving but not the bottom one. Turns out this is the one that is referee to as the drivers temp actuator.

I ordered the part from Rock Auto...less than $40 delivered. Came today and I just finished the install.

Now cool air blows out all the dash vents.

This install is not for the faint of heart or mechanically challenged. This actuator is tucked up behind a solid metal bracket that makes it impossible to gain access to the top bolt. I literally took a crow bar and bent that metal bracket out enough to allow access to the actuator.

The plastic sub frame to the dash on this side prevented removal of the actuator from off the shaft of the damper. I had to rig a come along Lully to pull this part back toward the door ...I secured the end of the pully to the seat bracket.

Once off the new actuator must be inserted onto the keyed shaft and then rotated into position for bolting up.

bmantlow
09-30-2012, 05:33 PM
I have the 2002 T/B 4WD LS. Mode Door Actuator clicking. I removed the actuator by prying with a flat tip screwdriver after removing the 2 small bolts. My part # is 52489426. What is the current replacement part # for this part? Just for reference mine has 3 actuators on the left side and this is the middle one. It has labeled in big letters HT and then in smaller letters 52489426 and under that# is 63312???A* I can't make out 3 of the letters.

So I need replacement part # for 52489426. :confused:

Thanks in advance..

bmantlow
10-06-2012, 06:40 PM
^^^^ My actuator I pulled had part# 52489426 on it, according to GM Parts that is the old # for Mode Door Actuator and Cam Assy. Just the actuator itself is now part # 89018539 and the aftermarket part by Dorman is 604-115. This solved my clicking noise. :)

mbergh
01-13-2013, 10:42 PM
I have a 2002 Bravada that after changing the alternator, I have only the defroster working. I pulled the fuse and turned the key to run and it cycles, but still only works the defrost. Is it the actuator?

bmantlow
01-14-2013, 12:47 AM
I have a 2002 Bravada that after changing the alternator, I have only the defroster working. I pulled the fuse and turned the key to run and it cycles, but still only works the defrost. Is it the actuator?



You may get more responses if you start a new thread.

Ray Dockrey
01-14-2013, 09:44 AM
I have a 2002 Bravada that after changing the alternator, I have only the defroster working. I pulled the fuse and turned the key to run and it cycles, but still only works the defrost. Is it the actuator?No need to start a new thread. Sounds like the mode door actuator. You can check but I bet you have air at the floor too. That is usually the position they fail in. Be prepared that on the 02's the actuator is glued to the shaft. You can make the tool you need to press it off. There are how-to's on here on how to make the tool. I was able to use a screwdriver and gently pry it off but a few who have tried that broke the shaft.

mbergh
01-15-2013, 11:16 AM
Mine is stuck at defrost only. No floor vents or dash vents. Tried the B 10AMP fuse several times and it cycles, but does nothing to change the vents. Rear heat vents work. Have to check threads to see what part number the actuator is for my vehicle and then follow the instructions. Read that it is NOT glued on some posts but that it's pressed on and requires a GM tool- but some have made their own tool. Was looking for confirmation before I lay on my back under the dash for a spell.

Ray Dockrey
01-15-2013, 01:33 PM
Did you read through this thread? There is a picture of the tool that somebody made. Mine was glued. When we worked it loose there was hard adhesive over run on the actuator. Here is another thread showing somebody making the tool.

http://forums.trailvoy.com/showthread.php?t=65280

mbergh
01-15-2013, 07:21 PM
Thanks! Sorry for posting a new thread but it got more than cumbersome to read through all the questions & responses. Now I just need to get the right part # and order it, make the tool as instructed, and give it a whirl.

mbergh
02-06-2013, 01:32 AM
Had only defrost. No vents or floor vents. Turns out both the middle actuator (mode door) and the defrost actuator (upper unit) had broken main gears. While driving I heard a ticking that was irritating and it would last several minutes, if not longer. I never knew what it was. I have a 2002 Bravada and both went bad. I changed the middle actuator marked MT and it was functioning. (I hooked it up off the door cam and saw it moving). I still had only defrost and middle vents, but no floor vents. If the defroster actuator is bad, it will not divert to the floor. Even if the mode door actuator is working. They synchronize and have to work together. More than 1 can go bad. I lived in Las Vegas from 2002-2009, then moved to Chicago. BIG climate difference. The heat, age and cold has been Hell on the vehicle. Lesson: if 1 actuator does not solve your problems, check the other actuators. My actuators have ony 2 screws holding them on. No glue. Just a snug fit on the door cam. Just a FYI.

monteman
05-21-2013, 11:51 PM
I've been working on my '04 TB and found this thread. I had all the symptoms that are spoken about here, air only on the top and bottom, not in the dash vents. Sure enough I found that my mode door actuator was bad. I figured I didn't have anything to lose because it didn't work anyhow so I took the case apart and found that the big gear was broken and allowing the metal shaft to spin. I took a Dremel tool to both parts to rough them up and applied JB weld to them. I will put everything back together tomorrow. I'm not sure how I will align the white gear to the vent door gear though. Like I said it was worth a try, if it doesn't work, oh well! I was going to buy a new on AC Delco one on ebay anyhow! I'll be sure to let everyone know how I make out! wish me luck!

dave5688
10-21-2013, 11:17 PM
I was having a problem with my hvac not switching to vent on my 06 tb. I replaced the mode actuator but did not know that it needed timed or set. I dont know where to set the actuator arm and door gear. when installed the actuator switches but when I turn the car off i hear the door close and then it wont switch location anymore. Any suggestions?