High Speed on Fan not working [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: High Speed on Fan not working


john_danielson
07-06-2007, 11:39 AM
Yesterday in the 108 degree Norcal heat, my high speed (#5) on the fan quit working. Speeds 1-4 are working fine. Do you think it could be a fuse or is there a separate blower/fan for the high speed? I have a 2006 LS TB.

tblazed
07-06-2007, 11:47 AM
Yesterday in the 108 degree Norcal heat, my high speed (#5) on the fan quit working. Speeds 1-4 are working fine. Do you think it could be a fuse or is there a separate blower/fan for the high speed? I have a 2006 LS TB.

Probably #35 the blower fuse in the underhood fuse block. The blower motor gets power from that fuse only in the high "5" position.

rbarrios
07-06-2007, 11:56 AM
on a road trip- my #5 stopped working so I said to myself- when I get home Ill research it on trailvoy..... Later on I happened to turn it to #5 and it started blowing again.
I did nothing to it.

tblazed
07-06-2007, 12:18 PM
on a road trip- my #5 stopped working so I said to myself- when I get home Ill research it on trailvoy..... Later on I happened to turn it to #5 and it started blowing again.
I did nothing to it.

I remember someone traced that problem to bad solder connections in the resistor ass'y at the relay that supplies full power to the blower. That could explain your intermittent loss of high speed 5.

blktbz
07-06-2007, 12:20 PM
I had this problem once before. It actually remedied itself, as one day it started working again by itself.:confused:

the roadie
07-06-2007, 01:09 PM
...resistor ass'y at the relay that supplies full power to the blower...If you have the electronic digital climate control, the fan speed is controlled by an electronic PWM (pulse width modulation) buffer mounted to the side of the fan housing. The resistor ass'y only exists on trucks with the manual climate control. John, what version do you have?

john_danielson
07-06-2007, 01:26 PM
I have the manual control. When I get out of work today, I will start with the fuse and the solder connections as I have have intermittent problems. Thanks for the replies.

rbarrios
07-06-2007, 04:45 PM
in 106,000 miles- my number 5 stopped working for maybe 20 miles?... then it came back to life.
Maybe it was a solder connection? I dont know- I just know it works now.
Maybe one of those bumpy mexican roads jarred it into operation again?

MCOMEAU334
07-06-2007, 08:01 PM
My fan speed 1 wasn't working, Blower motor resistor was the problem. Simple fix. It's behind the glove box and it's about $18.00 for the part. :):)

ehall0527
07-06-2007, 08:38 PM
Do you have to solder the new resistor in place or does is just "come off"? I'm about to replace mine since my 1 & 2 fan speeds don't work :mad:

GeorgeJL75
07-06-2007, 09:23 PM
No soldering required.

the roadie
07-06-2007, 09:41 PM
Probably #35 the blower fuse in the underhood fuse block. The blower motor gets power from that fuse only in the high "5" position.To add detail for future searchers to find, on HIGH speed, power comes from Fuse 35 (40A) and it also goes through the NO (normally open) contact on a relay on the resistor assembly board. Speeds 1-4 get powered from fuse #34 (30A), selected power goes through resistors and then through the NC (normally closed) contact on the relay.

If the relay contact is welded into the closed position, the coil has failed, or the wiring from the control module in the dash to the relay is open, the HIGH speed will be just as dead as if fuse 35 is open.

Scanned PDF from the manual (http://www.roadie.org/blower.pdf)

KNBlazer
07-10-2007, 12:50 PM
I just had to replace my blower resistor today... I had to cough up $57.16 at my dealer... it was the correct part number as it was cross referenced with my VIN... it is a new design as the new one did not look anything like the old one... I had lost fan setting 1 and 2 and the rear had lost A/C also ... now everything is swell... lol

Part number was

AC Delco #15-81095
GM # 89019100

the roadie
07-10-2007, 02:06 PM
Pics would have helped future researchers. Any way you can get some closeups of the old and new, so we can speculate on the changes? That's one of the most important activities on trailvoy.com - idle speculation and guessing! :cool:

SKFengineer
07-10-2007, 04:45 PM
I think I tossed the old one but the two did not look exactly the same, in fact I think the plug was even in a slightly different spot on the new one. As another note the replacement part was a GM part from the Fred Beans dealership, so don't let the looks fool you. Either way when I put in the new one in, things were back to working as good as new.

KNBlazer
07-10-2007, 05:08 PM
here you go then...

http://img231.imageshack.us/img231/3370/acresistorjp0.jpg

john_danielson
07-16-2007, 01:07 PM
After taking my TB to the dealer since it is still under warranty, it indeed was the resistor problem. They of course replaced it at no charge and the fan is working great again.

KNBlazer
07-22-2007, 02:17 AM
are you under the original 36K warranty? ... I have the extended 75K warranty but didn't feel like coughing up a 100 deductible since I would have to take it to a different dealer than the one it was originally bought from...

Motives
07-22-2007, 05:06 AM
When the blower motor resister on my Envoy went bad The blower motor continued to blow at high speed even when the truck was shut off:confused:. After looking it up here, I tapped on the relay portion of the assembly and the blower finally went off. I just paid $40 bucks and replaced it anyway. No more problems.:D

Bounty_Hunter
07-27-2007, 06:49 PM
Anybody have a pic of the blower resistor mounted behind the glovebox? Where exactly back there is it?

Thanks for all the great info.

KNBlazer
07-27-2007, 11:16 PM
Anybody have a pic of the blower resistor mounted behind the glovebox? Where exactly back there is it?

Thanks for all the great info.

there is no way you can miss it as it is just about the only thing that sticks out underneath...

trlblzr4life
07-28-2007, 06:41 AM
could be the #35 fuse or possibly the blower motor resistor i have had that happen to me on mine before very easy fix.

Bounty_Hunter
07-29-2007, 04:20 PM
there is no way you can miss it as it is just about the only thing that sticks out underneath...

There's nothing sticking out underneath, it's all covered by plastic. There is something similar on the left side as you look behind the glove box.

john_danielson
07-30-2007, 01:21 PM
are you under the original 36K warranty? ... I have the extended 75K warranty but didn't feel like coughing up a 100 deductible since I would have to take it to a different dealer than the one it was originally bought from...

Yes, I was still under the 36k warranty so I didn't have to pay the deductible.

Bounty_Hunter
08-02-2007, 01:24 AM
Check this, I replaced the blower resistor and now 5 works, but 4 still doesn't work. Could it be a bad resistor from the dealership?:weird:

Bounty_Hunter
08-05-2007, 01:58 AM
No suggestions?

KNBlazer
08-05-2007, 02:04 AM
No suggestions?

put your old one back in and if you get 4 back then you got a bad resistor....

Bounty_Hunter
08-08-2007, 11:14 PM
Check this, I replaced the blower resistor and now 5 works, but 4 still doesn't work. Could it be a bad resistor from the dealership?:weird:

Aggravated, pulled the new resistor out to return it and put the old one back in, fan now works on all speeds.:duh:

Bounty_Hunter
08-10-2007, 04:50 PM
Now I think it's a wiring issue, 4/5 stopped working again, reach behind the glovebox and grab the resistor wiring and it started working fine again. Anybody else experience this? What fixed it?

KNBlazer
08-10-2007, 05:10 PM
Now I think it's a wiring issue, 4/5 stopped working again, reach behind the glovebox and grab the resistor wiring and it started working fine again. Anybody else experience this? What fixed it?

you may want to look up there and see if there is any corrosion on the connector (harness) ... the old resistor also check it there may have been condensation and leaked onto the harness...
make sure you check one harness at a time when you get that problem again so you know which harness to go after

http://img231.imageshack.us/img231/3370/acresistorjp0.jpg

Bounty_Hunter
08-12-2007, 06:45 AM
I wish it weren't so hard to get to that harness. I'm going to have to find out exactly where the loose contact is.

There is no sign of moisture, only a little dust from where the resistor fits into the air duct.

bigdaddyvl
08-13-2007, 06:58 PM
Ok, now I have to chime in on this. I have a 2006 with manual climate control. My #5 went out last week. The two days prior to it going out, on the way home in the Houston heat, I smelled something burning. The first day I actually pulled over because I thought the truck was on fire. Could this have been the resistor thingy burning out or do I have another problem with my #5?

ehall0527
08-13-2007, 11:09 PM
The "5 Speed" fan setting does not run through the the resistor.

Bounty_Hunter
08-15-2007, 12:22 AM
Found my problem, here's the connector at the blower resistor. This could also be your burning smell as well. Any idea on what's causing this problem?
http://sija.org/bounty/Misc/TBburnt.JPG

KNBlazer
08-15-2007, 03:34 AM
Found my problem, here's the connector at the blower resistor. This could also be your burning smell as well. Any idea on what's causing this problem?
http://sija.org/bounty/Misc/TBburnt.JPG

interesting ... well if you are under warranty it might cover it but if not then time for a new project....personally...I would say it was the resistor that shorted that is most likely the 12v source wire...is that green right there, isn't that corrosion?... best way to take care of that is pop that connector out and buy a new connector and a butt end connector with some new 12g wire and hook it up and see if that holds.. make sure you take your resistor with you so you get the correct connector (not entire plug, just the single connector)....

the roadie
08-15-2007, 09:59 AM
I work on aging electronic equipment all the time, and see this kind of thing in 5-20 year old gear. Typically, the root cause is a connector female part that's a tiny bit loose and doesn't make a good low resistance connection. Some of the current going through it turns into heat because of the small resistance. With time, current going on and off in the connection causes heat/cool cycles that results in thermal expansion/contraction that reduces the springiness of the copper connection. Then the force holding the connection together goes down, the resistance goes up, and the self-heating gets worse. It's a vicious cycle that ends up with the heating being so bad that the nylon connector body softens, or the wire insulation chars/smokes/smells, or worse - melts off and the wire shorts to something and finally blows a fuse.

This effect happened to my built-in, 13 year old microwave's interlock switch. My wife thought she'd get a new unit out of the deal - it was really only a half-hour repair. Showed her! :woot: Oh, it took me a few months to actually take it out of the wall for that half-hour repair, so I still took heat for it. That's the way of the world. :sadcry:

Bounty_Hunter
08-15-2007, 11:46 AM
make sure you take your resistor with you so you get the correct connector (not entire plug, just the single connector)....

By connector, do you mean only the terminal on that one wire? I thought I would have to buy the entire plug.

It's not under warranty, and you wouldn't expect this kind of problem from an '05.

roboman
03-26-2008, 07:57 AM
Bounty_Hunter,

I am just curious if you fixed your issue?

I have a 2005 GMC Envoy that is basically doing the same thing. Speed 5 does not work at times. They Chevy dealer stated they changed teh Blower and the Resistor out. This was about 3 weeks ago. Yesterday Speed 5 went out again. Looking at it I tapped the panel beneath the glovebox and Speed 5 came on.

Does this seem to be a short in anybody's opinion? I am going to take the vehicle back to the dealership because they warranty their work.

the roadie
03-26-2008, 10:33 AM
Does this seem to be a short in anybody's opinion?No. Shorts blow fuses or connect two circuits that shouldn't be. Open circuits do what you're describing. But it's still a wiring problem, I agree. Some intermittent connector pin, or a wire that's been flexed and the inner conductor broken, can turn on and off with minuscule flexing or temperature changes or vibration.

roboman
03-27-2008, 08:01 AM
Well I took it back and it ended up being the wires were burnt at the connection of the resistor and it burnt the resistor up. Good thing though is I just had the resistor replaced 3 weeks ago and well I didnt know they have a 12 month/ 12,000 mile warranty on their items/service so I didnt have to pay a cent. I just had to sit there for 3 1/2 hours for it to get fixed.

willieconn
11-26-2009, 07:30 PM
My fan speed 1 wasn't working, Blower motor resistor was the problem. Simple fix. It's behind the glove box and it's about $18.00 for the part. :):)

What if the blower motor works but the dial 1-5 does not. Actually it stopped working on 4-5 then gradually 1-3 stopped. Could it still be the resister or the switch? :)

03LTTB
11-26-2009, 08:03 PM
Hmm i have similar prob

the roadie
11-27-2009, 02:18 PM
http://forums.trailvoy.com/showthread.php?t=32751

kip45223
01-04-2010, 01:42 PM
Last week got in my 05 TB with manual controls and the blower did not work at all.. Nothing on 1 thru 5. 15 min later all started working except number 5. Checked fuse 35 under the hood and appears ok. turned on the fan and 1-4 are ok, no 5. removed fuse 35, nothing at all. put back in, all but speed 5. should i check the actual switch or the resistor pack behind the glove box?dont want to buy a part thats not bad????

the roadie
01-04-2010, 04:03 PM
It's almost always the resistor pack, not the switch. But there's no way to get a 100% ironclad guarantee that you're buying the right part unless you have a meter and know how to trace schematics and get in there and troubleshoot it. Without that electrical knowledge, a bit of experience, and set of tools, you're always guessing and once in a while you're going to waste $$.