Why are the heater fan not working out of Pontiac 1997 grand prix?

Blower motor problems are common on GM products. If the fuse is good then the motor is probably bad. Using a 12V test light, check for current right at the motor. If there is current then you will need to replace the motor. If the motor works only on high, then the blower motor resistor is bad and will need replacing. I hope this helps you. Mark My ignition switch was bad. Wiggle the key in the switch and wee if the fan works! I had problems with my resistor twice. The resistor and fan motor are accessed from under and behind the glove compartment. so it is hard to get at. After replacing the resistor a second time I looked for a reason. The problem turned out to be a misplaced gasket located at the bottom of the windshield under the plastic cowling. The gasket wasn't re-installed properly at a local dealership when the car was in for a wiper recall issue. The misplaced gasket allowed water to flow down the windshield and directly into the heater fan housing, where the resistor is located. Incidentally - my warranty company refused to cover it stating it was water damage. Also, GM and the dealership refused to replace the motor or resistors which were damaged as a result of the shoddy workmanship at the factory, or at the dealership (or both). Come to think about it, I don't think I could even communicate with the manager at the dealership. I actually got into a verbal argument with the Service Manager, then the dealership owner didn't return my calls, or mail messages. I haven't been back to that dealership since.