Dear Cartalk, I have a 97 Pontiac Grand Prix with 3.8 L engine and about 127,000 miles. The ac blower has had an intermittent problem for several months. It would work some and then cut off. Now it is not coming on at all. When you turn the blower on, the daytime running lights go out except on the #5 (highest) speed. The rear window defrost light is not coming on when pressed either.
I researched the problem via internet and found a number of possible causes. These include blower, blower relay, climate control unit, wiring harness corrosion and ignition switch. I took the car to my regular shop. They diagnosed the problem as blower and blower relay which they replaced. It still didn?t work so they put back my old parts and recommended another shop specializing in electrical problems.
Are you familiar with this kind of problem? Any help you can provide is appreciated.
Sincerely, Phil.
If the chassis ground for the blower motor is bad, the blower may be seeking another path to ground. It is a simple matter to temporarily run a heavy wire from the positive terminal of the battery to the feed terminal for the blower motor. If the blower comes on, the ground isn’t the problem. If the blower doesn’t come on, then either the motor is defective or there is a problem in the ground.
I will give that a try & let you know the result. I guess my concern has been taking it somewhere that just starts changing out parts until it finally starts working. I’m told this “climate control module” is not cheap. Wonder if anyone ever bypasses these electronics to operate fans? Thanks.