Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

HVAC Mode Actuator door replacement

862K views 737 replies 338 participants last post by  Ravalli Surfer 
#1 · (Edited by Moderator)
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.

First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from parts4chevys. $46.33 which was a lot cheaper than the dealership.

Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.

Remove gray air duct as shown in pc #53; just pull it from its endpoint; this way you can get to the actuator better.

There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.

Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!

You can doooo eeeet!
 

Attachments

See less See more
3
#693 ·
Question about recalibration

Ok, so I do the recalibration (pull all the fuses, disconnect the battery, etc) and it works for 2-3 ignition cycles then loses the calibration again and I am right back to square one. is there something I am missing that locks the recalibration in, so to speak? :confused:
 
#694 ·
I went to gmpartsdirect searched for the part number you listed. I have a 2002 TB LS 2.4L but it states its the wrong part. The diagram for the 2008 shows It as the middle actuator under driver dash. So it's the same part I need to replace. But It only lists it as a actuator GM no specific details. So I searched again but there's no same part coming up for my 2002 model. I then went to auto zone just to see what it gives me. They lists it as a Heat AC blend actuator. There's three for my base model for the main vents. One is this "Main Air distribution mode Actuator Only." This ones $138 so I assume its the wrong one. It has two others in the $40-50 range one is listed as the "Main. Air distribution mode. Cam and Actuator Assembly." The second is listed for the "Main. Air distribution mode. Actuator Only." The actuator only looks like the part you have pictured but doesn't show clearly the white gear coming out the side. I want to order the correct part online to get the best price but not to confident I can find the right one. I'm a novice a repairs so this will be a more advanced repair. So any help is greatly appreciated.
 
#695 ·
I have a manual HVAC control panel. I just realized after searching again for the correct dash vent actuator part I have one other question. I saw this part "Recirculation Door Actuator; w/ Manual AC" for my 2002 TB LS. Since the recirculation air mode stopped engaging at the same time my dash vents stopped working I'm hoping the dash vent actuator is all I have to replace. Before when I have AC or heat on I push the recirculation button the light stays on when the dash vents stopped working I'd push it and now blinks a few timed then goes off. So is my assumption correct or does anyone know if these two functions require individual actuators? Also does anyone know where I can download the diagram of the entire in dash HVAC system. That would help determine where and if there a recirculation actuator for my 2002 TB LS. Plus help with future repairs. Thanks again.
 
#698 ·
2004 GMC Envoy HVAC Mode Actuator door replacement

OK, here are my issues. 1)no air from dash vents 2)only warm air on driver side defrost with cold air coming from passenger side defrost 3)actuator clicking noise from passenger back/rear of vehicle upon recalibration but no changes. So my questions are how many actuators and where are all located (I'm under briefly and see 2 actuators but have not looked terribly closely) which actuators to replace. I can get 3 different ones on Amazon for under 100 for all. Each states it performs a different action.
"left main - temp", "main-mode" & "right main-temp" need help quick as not much hot air available from driver defrost. Thanks
 
#699 ·
04 GMC Envoy XUV - Vents, Dampers, Actuators

I want to say THANK YOU to most of the comments in this thread. Very educational.
-----
I noticed shortly after replacing the batter (and yes following the hints described in several post) a few challenges
- AC would come on, but very little volume.
Solution: we cycled the modes and "wallah" everything was fine.

- But now, no air flow from the front vents at all, some from feet and dash, and rear seat vent works great (nice and cold plus strong fan).

Next step will be the fuse out option described and see if the bugger will play nice.
Again, Thanks for the info folks.
:thx
 
#700 ·
Just bought an 02 Envoy at auction need help with warm driver air

Hey guys. Glad to have found a forum for Envoys. I'm active on several diesel engine sites.

Anyway I went to auction, picked up the vehicle I went after (a 99 chevy dually with 6.5L). My wife went with me and found a really clean 02 Envoy and we were able to pick that up as well.

Great day at the auction.

The passenger and rear air blow ice cold. Driver side seemed weaker air flow and was hot. We messed with the controls for a while and nothing changed.

From internet searches I see there is "reset" procedure where you pull the fuse for a few seconds..then let the system re-calibrate.

Then..how do I troubleshoot from there? If I'm counting right there are 5 or 6 different actuators in there.

Looking forward to using this site a bunch.

NH
 
#702 · (Edited)
Just completed mode door actuator replacement

Thanks to the knowledge shared in this thread, I felt pretty confident going in. Job was pretty straight forward & went smoothly. It helps if you are not in a hurry and can get yourself off the floor of the vehicle to stretch once and a while!

The actuator was firmly on the mode door shaft and I was reluctant to lever too much on it for fear of bending or breaking the shaft. I ended up fabricating a tool from some 1 1/2 square tube I had in the garage... made the removal really easy.

I also pulled the old actuator apart and couldn't see any visible failure... I presume the motor or cicuit board failed.
 
#703 ·
I had a problem last week with my drivers side only blowing out hot air. I went and replaced the driver's side blend door actuator and now it goes from hot and cold when the dial is turned.

However I can't get the air to vent on the floor when it's selected. When I select floor it blows out by the windshield. The defrost/windshield and vent only work but not the floor. Is that an actuator issue? I see two other actuators above the gas pedal and I see one moving when I select the different modes.
 
#706 ·
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.

First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.

Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.

Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.

There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.

Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!

You can doooo eeeet!
 
#707 ·
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.

First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.

Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.

Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.

There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.

Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!

You can doooo eeeet!
 
#709 ·
I am installing as actuator and it seems like during the install it wanted to go in with the door closed , is this right ?
The actuator gear does not move and I was wondering if this is middle or the close point , Please help I want to get this completed.
HVAC Heater Blend Door Actuator on a 2004 envoy
 
#710 ·
Hi newer owner of an 02 Olds Bravada here. My HVAC is stuck on defrost, but can also blow out of the dash if I desire. Dual zone temperature controls still work but I have only the faintest breeze on my feet. Following this forums advice I tried resetting the hvac fuse, no luck, and I just put a new mode actuator in, still no luck. I may be too late to this party but if anyone can help me you guys can. SOS!
 
#716 ·
I just replaced my mode actuator due to the dash vents not working; it wasn't too bad of a job; you just need to be patient and smart as you work.

First you need to find out what part number to order; just call the local GM dealer. you will need to give them your VIN; the P/N I used was 89018675 and I got it from www.parts4chevys.com for $46.33 which was alot cheaper than the dealership.

Remove lower dash covers. The actuator is located behind the middle portion of the dash; if you lay on the floor and look to the left you will see it.

Remove gray air duct as shown in pc #53; just pull it from it's endpoint; this way you can get to the actuator better.

There's 2 actuators; you want the one with the white gear coming out the side; it's the lower one in pic #52. You will need a 5.5mm socket to get the 2 screws out; be careful not to drop the screws; take your time.

Pic #46 shows the actuator; the two horizontal holes are where the screws mount; the other one close to the wire connection has a dowel that helps locate the actuator. You will need to adjust the white gear shown in pic #46
to be at the same location as the gear on the actuator you removed in order for it to go back in correctly. There are 3 marks on the back of the plastic housing (as seen in pic #46) and also slots in the metal part of the gear drive, the top slot is in the 1'oclock position in pic #46. Be sure your new actuator gear position matches the old and it will drop right in. I put the screws in the socket and then wrapped electrical tape around them so the screw wouldn't fall out during assembly. The whole thing took me 45 minutes.
The vents now work like a charm and I saved a bunch of coin!

You can doooo eeeet!
Man the old days of floor vents and blending doors on a cable and a mixing damper to the heater core. Things were so much more reliable and simple. just fixed my fan resistor harness. Kept falling out. No fan. Now… onlry auto defrost.
 
#717 ·
OK. So, on my 2004 XUV with auto-ac, disassembled dash to inspect actuators. See 3, bottom 2 look within limits (3 marks), but top 1 (Defrost?) is WAY outside (read: horizontal). Multiple recalibrations haven't worked. So... How'd it do that? But more importantly, can it be easily fixed? Eg. Remove actuator, move door within limits, replace actuator? Exactly what needs to be disassembled to do so. What's with the 5.5mm socket I read about, do I need 1, and if so, where can I get 1. Thanks
 
#723 ·
I read a system code would be set if an actuator failed calibration, then thereafter that actuator would be disabled. If so, is there a way to check/reset the code without a Tech2 tool & laptop software?
I've added refrigerant a few times, some said they fixed leaks, and haven't seen the dye around the pressure switch recently. Is it possible the switch may be part of my problems? Will replacing it discharge the system? Sticker on air filter cover says 2.65 lbs (& dye) w/rear AC.
Anyone have detailed instructions/video on dash disassembly needed to remove driver's side actuators?
90°F+ typical here... need dash vents open! :(
 
#724 · (Edited)
That's a new one for me. I don't believe there will be any codes set for the actuators, good or bad..

I might be wrong, but my EXT needed 3 actuators and I never saw any SEL lit for that. All you'll get is a lot of clicking.

Freon leaks don't heal themselves. The only time they stop leaking is when all the freon escapes.

If you change that pressure sensor, you're gonna get a face full of refrigerant, refrigerant oil and refrigerant dye.

To confirm for yourself whether you have to pull the dash apart ... try go change that upper actuator first. If you have fingers like ET and can get it done ... so be it.

Don't count on that happenstance
 
#725 ·
My mother-in-law had been experiencing clicking before her face vents quit working. My wife and I have an understanding in regards to working on her mothers 2002 Trailblazer. I fix anything that goes wrong with it and in exchange, I am allowed to live. =)

Her 2002 has the Auto feature. The part I purchased at a local Advanced Auto was Doorman 604-115. It is different from the original post in this thread as it does not have the attachment. Most everything has already been covered in this thread. I happened to have a 5.5mm and both screws were only hand tight. The discussion about the plastic gears being glued or pressed, I would agree this part is pressed on. In my case, the actuator case slipped right off, but without the piece still connected to the plastic shaft. I've not seen that addressed here before. You can see the cracks in the plastic casing showing why the piece slipped out. I thought that might be why the actuator was not turning so I plugged it back in and it was still dead. I ended up using the large nail puller below. I was able to get it under the lip about half way up on the metal shaft still stuck to the plastic shaft. I applied equal pressure with my fingers on the back side and was able to lift it straight off with a bit of force. If you look at the plastic shaft, you can see the results of the original actuator being pressed on.

On a side note, my MIL first took this to a local shop, as I had just done some other work for her and she didn't want to bother me again. They charged her $100 to diagnose the issue and then quoted her either $500 or $2000, depending on which part was the actual probably. Well, they knew what the problem was. They were just covering themselves in case they had to pull the dash after breaking the shaft. I paid $53 for the part and spent a couple of hours on the research/repair. Kudos to all who have contributed to this thread.




Hood Automotive tire Automotive design Bumper Material property

Hand Finger Household hardware Thumb Nail

Automotive tire Camera lens Finger Thumb Rim

Automotive tire Motor vehicle Automotive design Bumper Automotive exterior
 

Attachments

#728 ·
This one will not disappoint: I started hearing that godforsaken clicking after hooking my battery back up from changing my injectors. Knew what it was, got the part, read around here to get an idea of the time I'd need and slated it for the weekend.
Before I continue, I just want to say that anyone doing this thing in under an hour or in less than 2 days, is either greatly exaggerating their wrenching skills or stands at a height of 18". Or both. Save your breath, I will not be swayed from this determination.
Anyway, I wound up pulling my seat out which made it exponentially more comfortable for an old fart like me, and I commenced to extracting this carefully nestled little device from its home. Sparing the reader all the gory details we can fast forward to the completion of my first install attempt. Something told me to keep my head under there for its maiden voyage. I didnt have the two gears meshed right and I could see it as soon as the key fell forward in the ignition. The 2 subsequent tries ended in the same maddening fashion so I braced up for a good hissy and pulled it off a forth time. In my sassy rage I disconnected both pedals and forced my head up there to see what fresh hell the gods at GM had wrought upon us mortals. All I could do was laugh entire paragraphs of curses at no one exactly because if I would have looked that far up there sooner, instead of doing it all by feel, I would have seen the 1" by 1/4" piece of tape that was crushed, accumulated and impacted in teeth of the black gear and saved my self a few hours of aggravation and borderline frostbite on my extremities.
I have no idea where it came from and I don't care at this point. I pulled it off, finished installing the new actuator
Ruler Office ruler Wood Rectangle Font
, fired up the truck and cranked the heat to 90.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top