My 1983 P'up shares the same system (in fact, some of mine was pulled from an '89 Trooper). I have the same issue, but have not yet found the time to troubleshoot.
There's no foam filter. I doubt the blower blades are the issue, whether dirty or not. But the blower housing is on the far right side under the dash, with a bowl-shaped bottom. The flange around the top, and the motor itself are held by 3 Phillips head screws.
It seems to me there are three possible causes for the blower output to be low:
There's no foam filter. I doubt the blower blades are the issue, whether dirty or not. But the blower housing is on the far right side under the dash, with a bowl-shaped bottom. The flange around the top, and the motor itself are held by 3 Phillips head screws.
It seems to me there are three possible causes for the blower output to be low:
- Voltage drop due to deterioration of connectors over the years (any connectors in the circuit).
- Failure of the fan speed control resistor assembly. The speed control rarely fails at the "High" setting, because it bypasses all the resistor coils. They normally fail on lower settings that use the coils.
- The fan itself (worn out)