Blower only works on 5

My interior fan only works on setting 5. Everything else is working fine, like the heat and A/C, just not fan speeds 1-4. Any ideas as to what the problem is, and how I can fix it? Thanks.

I say the switch is bad.

That's what I thought the problem may be too, but it's not. I know this because I changed the switch from my girlfriends Grand Prix to test if it was the switch. Her switch doesn't work in my car, and my switch does work in her car, meaning the switch is ok. Does anyone have any other suggestions?

I would try asking the question at:

GrandPrix.net forums (http://www.grandprix.net)

Grand Prix Owners Forums (http://www.gp-owners.com)

those 2 places are great for finding info and stuff - try there.

Speeds 1 thru 4 go thru a blower motor resistor mounted forward of the blower motor underneath the passenger side hush panel. Speed 5 doesn't go thru the resistor. I have changed at least 100 of these in the last few months. The problem is the resistor ets wet and shorts out. Replace the resistor with the updated part from GM!

To Flatrater -

Thanks alot for your tips on this problem - it saved me a ton of time. I was
able to remove the resistor and repair it the corroded circuit traces on the
resistor printed circuit board. I'm viewing this as a temporary fix until I get
the replacement part.

Did the part mfg update the part to make it more robust, like maybe cover
the entire part with a durable plastic or epoxy that would prevent moisture
from corroding the circuit traces?

Thanks again.
:)

The new resistor is an improved design that addresses the corrosion issue. The AC DElco part number is 15-80571.