Ok, this is a very common problem with the pontiacs. You have a Blower Motor Resistor that increases the resistance to the motor for each level of fan speed. If you go to High, or speed 5, this eliminates the resistor, and if the fan runs fast, then you know your fan is good. If the fan doesnt run good in the high position, then it may be the fan motor going bad.
However, if the fan runs good in high, then most likely the blower motor resistor is bad.
This is located between the blower motor and the firewall. It is screwed into the airstream of the ducting. All you will see is the connector and two screws. Remove those two and the assemplby will drop out of the duct.
Do not over torque the screws going back in. You can crack the new resistor and then you will be right back where you are now. The screw torque is 9 inch pounds.
All in all, this will not be a hard, nor expensive repair. Might I suggest getting the new parts from www. Gmpartsdirect. Com they will be a lot cheaper than the dealer, but they will be the exact parts the dealer uses.
Monday, July 24th, 2006 AT 3:20 PM