GMC Repair: heater, blower motor resistor, heater blower

Question
I have a1998 buick lasabre limited edition. My heater blower isnt working as it should. It goes from high speed to low, shuts off even if its cold. sometimes when I turn the car off and wait for a few minutes and then turn it on again it will kick in. this is winter and i need my heater. what could it possibly be? Also it takes it time changing from the floor to the middle.
Don

Answer
There are actually two possibilities for your issue. First is the blower motor resistor as you stated as a possibility. The blower motor resistor is usually located inside the blower motor housing unless the blower motor is mounted horizontally and is accessible from the engine bay (which I do not believe is the case in your Buick) in which case the blower motor resistor is going to be located in close proximity to the motor.

The other possibility is that the ignition switch is going bad. Now, this may seem strange at first, but GM ran much of the power for the accessories through the ignition switch and as a result, carbon builds up on the contacts and starts to affect the operation of the accessories. However, I don't think this is the case in your issue as that is normally accompanied by issues with other accessories like the radio and such.

I think it is more likely that the blower motor resistor is bad in your case. I believe your blower motor is located on the passenger side, against the firewall close to the center console. If you contort yourself in a way where you can look at the bottom of the blower motor housing you may see a connector on the bottom, or a small access panel. If so, that is likely the blower motor resistor.