Blower Motor and Automatic Headlights Intermittent

[SulkierLizard]

Hello guys,

I have a 2000 Grand Prix SE 3.1 L with around 150,000 miles on it. Lately, the blower motor has only wanted to turn on setting 5. I don't think setting 1 has ever worked. It will sometimes turn on randomly if I leave it the high setting. It seems to have problems the most at night when the automatic lights turn on. My automatic lights will turn off, but they will turn on if I turn the switch on manually. I did a little searching and found out it could be the ignition switch or blower motor resistor. What do you guys think?

Thanks guys!

[GTP Dad]

If it works on 5 but not the other positions then the resistor is bad and needs replaced.

[SulkierLizard]

When it's working then it works on 2-5 for the most part. Sometimes it will turn off if I switch it to anything lower than 5. For the most part though it will blow on 2-5 (when it's working). It's just that when it's not working neither are automatic lights. There have been times when I have forgot to manually switch the lights on and flip the air on and bam! The lights will turn off when I'm driving. It's quite the bitch.

[Tech II]

Need a schematic to see if a power leg or ground is common to both circuits...

[olopezm]

The DRL's and blower motor intermittent operation sound like an electrical gremlin to me, do you have any other problems like the lights in you DIC (center console) won't light up or anything similar? Do you have a hard time getting the key out of the ignition cylinder sometimes?

If any of the answers is yes then it is very likely you have a bad ignition switch more than a blower motor resistor.

Oscar.

[GTP Dad]

Sorry, I missed the headlight issue. I would change the blower resistor regardless, it is cheap and can cause other issues if it is going bad. The ignition switch could be the problem because if you are getting intermittent contact on one of the switch contacts it may not be sending proper voltage to the various components and therefore causing the issues.

[gmtech1]

I ran into this EXCACT problem about a month ago, was the ignition switch. The headlamps and fan run off the same power ckt from the ignition switch. Was able to moniter the voltage on the ckt and watch it drop out. Replace the ignition switch.