Blower Motor overide

[Noto81]

I've run into the problem of my blower not adjusting speed a few weeks ago. Took it to the dealer and they replaced the control module. That worked for a week and half and then stopped working again. They looked further and there was a bad ground going to the resistor which caused the 2 wires going to the resistor to be "hot". That worked for a couple weeks and just yesterday the blower speed wouldn't adjust according to the control again.

Called the shop this morning to see what can be done about my problem. The service adviser said there is a design problem with those resisters and GM is working on a solution. In the mean time he suggested to shut off the climate control completely when shutting of the vehicle, and then turning it on after the vehicle is started. I guess it has something to do with having the fan on when the vehicle is started.

 

[AcSlayer]

I say ummm I will give that a shot next time I drive it. We do not drive it much due to the fogging up issue. Let me know what happens with yours.

 

[Noto81]

I've tried it 3 times now and its worked each time. The hardest part is remembering to shut the fan off before i turn the truck off.

 

[AcSlayer]

yesterday I went out to try your trick and my battery was dead. Thats what I get for letting it set for a week and a half. Anyways started it today and tried it, no go! As a matter of fact I started my truck a 1:34 and the blower never kicked on until 1:49. This is getting old.

 

[Noto81]

That sucks man, don't know what to tell ya.

 

[scribble]

#PIT5141A: Blower Motor Inoperative After Blower Control Module Replacement - (Feb 15, 2012)


Subject:

Blower Motor Inoperative After Blower Control Module Replacement

Models:

2004 - 2007 Buick Rainier
2003 - 2006 Cadillac Escalade Models
2003 - 2006 Chevrolet Avalanche, Suburban, Tahoe
2003 - 2007 Chevrolet Silverado Classic, Trailblazer XL
2003 - 2009 Chevrolet Trailblazer
2003 - 2007 GMC Envoy XL, Envoy XUV, Sierra Classic
2003 - 2009 GMC Envoy
2003 - 2006 GMC Yukon Models
2003 - 2004 Oldsmobile Bravada


With Auto HVAC System



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This PI was superseded to update administrative details. Please discard PIT5141.
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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:


In some rare cases, after replacing the Blower Motor Control Module with part number 89019351, the blower motor may be inoperative. This issue may occur if the blower motor speed is set to any speed position, except for low, when the key is turned off. Upon the next key up, the blower motor may be inoperative.

Recommendation/Instructions:


Engineering is aware of this issue and currently working on an updated blower motor control module. In the meantime, before turning the key off manually adjust the blower speed to the lowest setting. During the next key up, once the blower motor has ran on low speed it will continue to operate when adjusted to any of the other blower speed settings.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

[91RS]

Auto HVAC does NOT have a blower resistor. Your problem is most likely either the blower control module (different from the HVAC control head) or an ignition switch.

 

[AcSlayer]

ignition is a new one to me. Does any of this issue make a difference that it also does it in the summer when trying to use the air?


If I were to replace any part myself in hopes that I nail it, what should I change first?

 

[91RS]

I would change the blower control module first. Usually there is an updated connector and you'll have to splice it in.

The ignition switch usually would make it not work until the ignition is turned off and then back on.