Main blower under the dash will not shut off

JOHNMCGUIRK

MEMBER
2004 PONTIAC GRAND PRIX
6 CYL
AWD
AUTOMATIC
98,000 MILES

My main blower under the dash will not shut off when I turn off the ignition. I read it might be a relay, but I called the auto parts store and they said it could be a few things, including the blower motor, but I would have to take it in to be looked at. Right now, I have to take the fuse out when I shut my car off, so my battery won't drain and when I drive the blower is stuck at high speed. Thanks for your help.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

They are correct that this could be a relay shorted keeping it on, but this vehicle doesn't use a relay for the blower.

The control module uses a resistor called a control processor and a simple fuse for the circuit protection.

So, this means we need to suspect the resistor is the issue.

There is power going to the resistor at all times so when this shorts out it can keep the blower on even if the key is off.

You can confirm this by checking the voltage from the control module to the resistor and there will not be any but there will be voltage from the resistor to the blower motor so that is why it is staying on.

https://www.2carpros.com/articles/how-to-check-wiring

Please run through this info and let us know what you find.

Thanks

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