blower motor resistor?

socram · 02-21-2008, 11:20 AM

2000 grand prix v6 3.8

Blower motor quit on me 5 months ago and I replaced it w/o a problem. Been working fine until it just stopped a few days ago. No whining, just plumb stopped. Then it came on for another 10 minutes only in the "4" position. Then it was gone.

I bought another blower motor and tried hooking it up to see if that was the issue. hooking that up (w/o removing the other motor) did not fix the issue - still nothing in all settings.

I tried testing the wires that connect to the motor with a little tester that I have - nothing fancy it just glows red if there is positive voltage in the wire and green if its negative. When I test the connector that the motor plugs into, the black wire is negative regardless of the setting. the purple wire shows no current in 1,2 and 5 and positive current in 3 and 4.

Is this a resistor issue? I don't understand why there should appear to be current when its set to 3 or 4 but then have the fan not blow when its hooked up and on those settings.

Any place else I should look?
Thanks
Marcos

brcidd · 02-21-2008, 11:57 AM

With motors- you need to always test for voltage with a voltmeter- WITH the motor plugged in- often time you can show voltage unplugged- but plugged in there is none- why? Because of a bad connection that cannot pull current (amps) through it- at least not enough to run a motor!!

So with that in mind- you can re-test- or change the resistor/relay control in the HVAC box which is the most likely culprit- follow the purple wire back to it....it is a real PITA to get the 3 5.5mm screws out- but the back two are slotted- so they need not be removed completely- best to leave them in halfway if you plan to put them back in...use a universal swivel joint attachment on your 1/4" socket set

richtazz · 02-21-2008, 01:06 PM

IS there any signs of water intrusion in the heater box? Grand Prix's are known for failure of the cowl seal at the HVAC air inlet. If this seal fails, it allows water to get into the heater box, which will in turn short out the resistor and/or motor. I've seen a couple where the resistor was caked with ice/snow. You'll have to remove the plastic cover near the firewall on the passenger side to gain access to it. If the seal failed, you'll need to get some RTV to make a new one. I'd also install a cabin air filter for a like year Buick Regal (they won't list one for a Grand Prix because even though the spot is there, they didn't put one in from the factory on the GP's) while your in there. The cabin air filter will keep dust and debris out of the system and prolong the life of the components.

ICCS · 05-22-2008, 03:00 PM

Quote:

Originally Posted by richtazz

IS there any signs of water intrusion in the heater box? Grand Prix's are known for failure of the cowl seal at the HVAC air inlet. If this seal fails, it allows water to get into the heater box, which will in turn short out the resistor and/or motor. I've seen a couple where the resistor was caked with ice/snow. You'll have to remove the plastic cover near the firewall on the passenger side to gain access to it. If the seal failed, you'll need to get some RTV to make a new one. I'd also install a cabin air filter for a like year Buick Regal (they won't list one for a Grand Prix because even though the spot is there, they didn't put one in from the factory on the GP's) while your in there. The cabin air filter will keep dust and debris out of the system and prolong the life of the components.

Hey there,

If I can jump in here? I just changed the resistor and noticed it had rust on it which says some water did get in. This is the second time I've had to change the resistor, the last time was around 3 years ago. While I had the blower motor out I looked up the duct and noticed something white up there. I couldn't reach but I assume it's a cabin air filter? Is there something else up there that could be white? Assuming that the car has this filter, then the source of water is coming from elsewhere. PLEASE don't tell me I have to remove everything I just did to check and repair the cowl seal at the HVAC air inlet. Also, what does this HVAC air inlet look like?

Thanks,

Pete.

richtazz · 05-22-2008, 04:25 PM

Sorry ICCS. This thread is close to 3 months old with no resolution from the OP, so I'm going to close it. I'll answer your water intrusion issue in your own thread regarding your blower motor resistor.

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