Originally Posted by RickyN29
So wait, on my 90, what is the sensor with two wires coming off that screws into the radiator? It was my understanding that this was the coolant temp sensor (also controls the aux fan)
Reason I ask is my aux fan does not seem to come on when the jeep gets hot. it turns on fine with the AC, everything checks out fine at the relay, and I also have it wired to an override switch which engages the relay just fine.
YUP! The Thermo switch (which is located ON THE RADIATOR) on pre '91 XJ. That is the switch that controls the ELECTRIC FAN. But, I did this: http://www.off-road.com/jeep/cheroke.../radiator.html
So when I replaced the radiator, it didnt' have a place for the thermo switch, so I purchased an Adjustable Thermostat from Kragens. It's just as good as the stock Thermo switch, but i can adjust it to work the fan at what ever temperature I choose.
Oh by the way, I this also allowed me to add a manuel Electric fan switch (to throw on when ever I want the fan to work without waiting for the thermo switch).