As you may be aware, the controls for the AC fan leave a bit to be desired. First, the fan control is tied to the AC so, you have to run the compressor if you want the fan. Second, the three speed levels are inadequate. Kuehl/ Griffiths sell a Pulse Width Modulation (PWM) controller for the fan which seems very nice but I am too cheap to spend $250 on something I can make for <$50.
PWM controllers can be had from Ebay for $20 and will provide full range, variable speed control. Small push button switches can also be found on ebay to allow separate power to the compressor.
The wiring for my ’87 (yours may vary) is as follows:
Run the new motor control wires (#10-12 stranded) from the new controller through the grommet into the “smuggler’s box” and connect to the motor. Run the potentiometer wires to your center console or wherever you have the fan knob mounted (mine is under the ashtray). Power comes from the disconnected plug.
Mount the new controller to the bulkhead.
Variable fan speed control and the ability to run the fan separate from the AC compressor and condenser fans. Success.
Originally, I just used the original center console control box with the new fan knob mounted under the ashtray. Later, I designed and 3D printed a much nicer box.
