GMC Repair: Heater Blower Motor, blower motor resistor, suburban 4wd

Question
I own a 1990 GMC Suburban 4WD (350 5.7L engine) and this afternoon, the blower motor to the heater just stopped working.  This morning it was fine (and just about run me out of the truck with the heat).  There is heat coming out of the vents, just not able to get the fan to blow the heat around.  I just aquired this vehicle so I don't have a manual on it yet.  Could you tell me how and where to check the blower motor to see if its bad?  And where the wires are located to check them.  I have checked the fuses and know that its not a fuse.  Thanks so much for any help you can give (and wouldn't you know it, the blower motor does this just as the weather gets cold again...uggghhh)

Thanks again,
Evelyn

Answer
I do not have an electrical schematic for your particular vehicle in order to look up the proper information.

There are a couple of possibilities that cause this:

1. A faulty blower relay.

2. A faulty blower motor resistor.

3. a faulty blower control module.

4. A faulty blower motor.

5. Any number of wires from any of the above 4 possibilities.

I'm not sure if the blower motor is in the engine compartment mounted on the firewall by the radio antenna or possibly under the dash on the passengers side as I do not have a book for your specific vehicle.


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