This is a hack to turn the retarded comfort/power switch into a useful fan control switch. Note that this only works for RENIX cherokees.
First, under the hood find the sensor going into the driver side of the radiator and cut the wires. Splice the connector end onto a new pair of wires going through the firewall (needs to be long enough to reach the switch location). I used butt splices here for better heat and vibration resistance.
If the sensor was unplugged, then knowing this location will be helpful. The fan control plug is between the ballast resistor and the air box.
Ok, now tear open your dash. Remove the cigar lighter, the clock, and the panel with the transmission switch on it.
Cut the three wires going to the black plug on the back of the trans switch. Twist the harness side tan and black with yellow stripe wires together to lock the trans in power mode. If you like comfort mode better, just tape them off. Tape off the solid black
ground wire for safety's sake, since its right by the cigar lighter. Twist and tape the wire from the sensor plug through the firewall to the tan and blk/ylw wires on the switch side. This will cause the power setting to short the wires, and turn on the fan.
Bolt it all back together, and enjoy the manual fan control, while maintaining a clean dash look.