I have an 02 silverado 3500 dually with the automatic climate control and the fan stopped working. I thought I had trouble shot that the issue to the control module but I replaced it and it turned out to not to be it, I have replaced the blower motor as well so that side of the truck is new. The side 25amp fuse is good, as well as the 30 amp under the hood. Wondering what else this could be, the power wire plugging into the control module has 3 wires, sorry but I can't remember the colors, the outside 2 are positive and negative and are live. The center wire I can't get any reading on, either voltage or continuity, this is taking me up to the switch I think. But before I start throwing more money at it I wanted to talk to some other people. The parts store guys gave up after the control module. So any help would be awesome...TIA

 

Ryan, I'm having the same issue. I have a 2006 Silverado 1500 LS with center console and dual climate Auto Temp Control. I measured 4 to 12 volts at the connector to the blower (it would vary with fan speeds). at the connector module, my friend measured nothing on the center signal wire like you said Ryan(Voltage reading Ground to center signal). The other wire(red?) is full 12 volts. When he measured from the full 12v wire to the center signal he got variable voltage, meaning it may be a potentiometer that is just regulating the resistance, not the voltage of the circuit. I was hoping I just got a new faulty motor but it sounds like not the case. Thanks for starting the thread I'll keep searching.

 

Was it the Blower Control Module/Resistor assembly that was replaced? The HVAC control unit provides a pulse width modulated signal to the Blower Control Module to control the fan speed. Do you guys have access to a bidirectional code scanner? You may have a GMLAN communication issue in the HVAC system.

 

Yes I replaced the blower motor control module. I will check and see what scanner he has. Thank you!!!