I have an '04 Avalanche and my air conditioner is stuck on high and won't turn off even with the truck shut off. I tried replacing the resistor module but that didn't stop it. My buddy has said something about a high relay that is connected straight to the battery, but we can't figure out where it is. Does anyone know what that is and where to find it? Or does anyone have any other ideas?

 

do you mean your blower motor fan is stuck on high?
auto or manual hvac as the system are totally different?



there are 3 tsb that address this issue. here is one


#03-01-38-015A: HVAC Blower Motor May Run Continuously After Vehicle is Turned Off (Replace Blower Resistor Relay) -

 

Yes it is stuck on high. It won't stop blowing even if the truck is turned off. I have already replaced the blower motor resistor.

 

any burned terminals in the resistor wiring harness connector? There is a tsb for this in Canada.

#06-01-39-002C is a tsb for replacing the blower motor control module. Check for power coming out of the module when the module is off.

 

Sorry. It is an auto HVAC. I changed the plug in to the blower resistor when I put the first new resistor on it and I haven't noticed any terminals that were burnt up.