Chevrolet Repair: 1980 chevy suburban, heater fan controls, chevy suburban, heater fan

Question
my heater fan motor works but - the controller that mounts in the a/c box on the fire wall did not seem to be functioning properly, you could take it out and manually move parts in it to get the fan to change speeds. the fan is always on and on low it will not adjust even though the controls are in the high position. I have replaced the controller at the firewall with no effect - how can I fix this problem or even jump it so I at least have a high speed on the fan?

Answer
It sounds like you ahve a bad blower controller.  YOu need to check the voltage to the van and check the switch.  You could apply 12v to the motor and it will run at full speed.  The controller is basically a set of resistors that drop the fan amperage to lower the speeds.

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