Electrical Mistery - Blower Motor Not Working
Hellow all. I introduced myself on the intro forum, but it might be
appropriate to let you all know I am a newbie to the site and enjoy all the
great postings and advice. I'm a saturday mechanic working only on my own
cars. I'm reasonable at troubleshooting and general repair.
I lost all four low speeds on my Pontiac Grand Prix GT (3.8l V6 no turbo), but the blower works in high speed. I replaced the blower resistor and verified that both the new resistor and blower work by jumping power/ground to each resistor terminal and the blower runs through several speeds.
The weird part is that the headlights go out whenever I switch into any of the low speeds - that is when it is night and the automatic lights kick in. I can manually turn on the lights with no interference with the blower motor circuit.
I noticed that the DRL (daytime running lights) control module shares some circuitry with the blower circuit so I replaced that module with no success. Ouch - $100 wasted.