QuestionQUESTION: Intermittent problem on 2002 Pontiac Grand Prix GT (3.8 L). The Blower Motor / HVAC will turn on intermittently.
Noticed also that the running lights will turn on and off on the same intermittent frequency. Blower on, Running lights on. Blower off, running lights off. Best chance to make them turn on is to turn the ignition key off and then on again.
Seems to work more dependably if blower motor is on high. Sometimes if the blower does turn on and is on 5, when the switch moved to another speed, say 4 or 3 it may turn off again (at which time the running lights will also turn off).
Since the running lights and blower seem to be unrelated, would this a relay of some sort that affects both circuits?
ANSWER: Hey Steve:
This could be a couple of things. It's a power or ground issue. More than likely a power problem. I would look at 2 things. The most common thing is an ignition switch. I'm sure you have more than what you said not working you just haven't noticed it.. You probably have a bad set of contact in the ignition switch and when the fan is on high it's overlading the contacts due to the higher amperage draw. when it acts up if you have a volt meter check the fuses in the fuse box behind the glove box my guess it you have more than a few fuses that are loosing power. You can trace it back to either the switch or the other place is the pass thru between the engine compartment and the cabin. there is a wire harness that goes though the fire wall and water has a tendency of collecting in the rubber boot where that harness goes through and it corroded the power feed to the ignition switch. That is on the right side of the dash just above the hush panel and it's a big harness with maybe 40 wire in it. Pop out the rubber plug that insulates it and hold it in place and just give the harness a small tug inward to the cabin and if it's wet you found your problem more than likely. it's usually a red wire that corrodes. The problem is the drain for the HVAC drip right on that harness. Good luck :)
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QUESTION: Hi Todd -
I was able to make this happen once more checked the fuses. No voltage. As far as removing the hush panel, is there a way to take this our without breaking the clips or causig other damage (or do I simply need replace the clips)?
If it is the starter contact and not rusted out contacts at the fire wall, where is this located?
ANSWER: Yes they break off when you remove the hush panel. the contacts I was referring to are inside the ignition switch. did you check the fuses with a test light or a volt meter? A volt meter is best that way you can see if there is absolutely no power or just a small amount of it. My guess is that it's an ignition switch and not the wires in that pass thru because if it were the wires it would not be that intermittent it would be that way most of the time and even worse when it's wet out. At the big connector where the ignition switch is located under the steering column check to make sure you have power on the red wires those are battery voltage and you should have power out when the key is in the run position on a few of the wires as well maybe a white one and a brown one? best thing to do it when every thing is working check to see what has power when the key is in the run position and when it's acting up check to see which of them are missing power. Sorry I don't have a schematic to look at to tell you which wires for sure but you get what I'm driving at. If your missing power then the switch is the cause. Good luck :)
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QUESTION: Just for clarity - checked the voltage at the fuses with a voltmeter and it was 0.
I will now check into the ignition switch as that is where the problem looks to be from your answer.
AnswerYes check the fuse for the HVAC it should have battery voltage on both sides of the fuse. when it's working okay if and when it cuts out check that fues again and if there is little or no voltage then you have found the problem. There will be more than one fues that's loosing power if I remember correctly you have some kind of light issue as well I'm sure they are tied to the same problem. Just trace it back and like I said My guess is the ignition switch.
