blower motor

[cpisani70@aol.com]

03 GMC The blower motor runs constantly even with the ignition off and the key off. I had a messed up headlight switch the plastic clips that held the switch together were broken at about the same time this blower problem came about until I had enough money the best I could do was glue the switch that held for a short time and the blower trouble went away. I bought and installed a new switch all good there BUT still have the blower issue any help would be great it is getting cold cant leave the blower unplugged anymore

[clinebarger]

Automatic or manual air?

[cpisani70@aol.com]

Auto with air

[clinebarger]

Originally Posted by cpisani70@aol.com

Auto with air

Im not sure we are on the same page? Does your HVAC control head look like this?

[cpisani70@aol.com]

No sorry didnt know what you were asking it is manual

[clinebarger]

Can you control the blower speed with the key off? Or is it stuck on high?

If its stuck on high I whould suspect the blower motor resistor/relay assembly.

[MattA]

Most likely blower resistor, and also check the connector.

[neo297]

Originally Posted by clinebarger

Im not sure we are on the same page? Does your HVAC control head look like this?

I have a 2004 yukon xl with the same problem. The fan at times just would not blow even with the bars on the display at full then today it started staying on after truck was turned off not blowing at highest speed but on with key out. I have the controls like you show in your pic is there something different I need to check. I pulled the front blower fan resistor I have only a three lead input the resistence between the purple power wire to the motor is no resistence between ground, 7000 to input and 900 to battery terminals. I have chiltons manual but it does not show my type of resistor or how to check. Thanks in advance .
Paul

[clinebarger]

Originally Posted by neo297

I have a 2004 yukon xl with the same problem. The fan at times just would not blow even with the bars on the display at full then today it started staying on after truck was turned off not blowing at highest speed but on with key out. I have the controls like you show in your pic is there something different I need to check. I pulled the front blower fan resistor I have only a three lead input the resistence between the purple power wire to the motor is no resistence between ground, 7000 to input and 900 to battery terminals. I have chiltons manual but it does not show my type of resistor or how to check. Thanks in advance .
Paul

On the Automatic HVAC system there is no resister pack like on the manual HVAC system.
It uses a Blower Motor Control Processor. The processor is most likely the problem, but without a Tech 2 scan tool to help dianose it proporly were just guessing. Heres a diagram & trouble tree.