04 - 06 Grand Prix Owners who are stuck with the analog climate control module have come across the ever popular "Blower Motor failure" issue which ALSO causes OVERHEAT issues. This is a separate issue from the blower motor not turning off due to a voltage spike from the Wiper motor. The blower motor quits working which (I don't fully understand it, but it's all that makes sense) tells the cooling fans not to run. More on this later. I installed a new blower motor, and a new blower motor control module and still no luck. The only other piece down the line was the climate control.

In november '09 I came across this problem intermittently and by slapping the blower motor shield or side of the dash console (which contains your stereo and climate control). I replaced the blower motor, and it worked for all of a week before it failed again. Each time I was experiencing extreme overheat issues if I did not keep the car moving. It was fine on the highway even in the hot summer.

I rigged up a fuse and switch to get the blower motor working (which fixed my initial problem of not having any HEAT!) and VOILA! my cooling fans started turning again (Only with the AC Turned on, as I believe there is an air sensor of some sort that detects air flow that tells the fan relay to close and turn the fans on). After a few months of using the switch to turn the fans on w/ the AC to cool the engine inside the city I finally found a used climate control unit.

I installed the new climate control unit and rewired my blower back to the control module, turned the key and everything started working. The cooling fans kicked in at the proper temp w/o the AC running, as well.

I believe this was a separate issue from the wiper motor, but the climate control is up the line between the wiper motor which feeds the 12V and the climate control -> Control module, so I may be wrong.

It is definitely something that needs to be solved completely.