Another......Aux Fan not turning on thread

I have searched and read many threads but I still don't know what to check next.

I have a 1987 4.0 XJ Idiot lights no guages (looking for a replacement cluster)...the fan has never came on.

My AC doesn't work...I believe it has a leak and no freon. (Near future project)

I have hooked the fan to the Battery and it works fine.

I have changed Relays and cleaned terminals still doesn't work.

I started to trace the wiring but the harness and wire looms got rather confusing.

I have looked at fuses......not sure if I checked the right one but looked at all that I could find.

Any suggestions to where I should look. I have considered wiring in a manual switch but I would like to get the original setup working first. Please help.

Thanks, - Tim

I ran into the same problem you have a few years back. I finally bought a full gauge cluster and installed it with the needed sending units and found that I was indeed running a little warmer then I had originally thought. I put a manual switch wired through a relay and have not had to worry about it since. I have since then istalled a cooling system out of a 99 and did away with the old system. My temp hardly ever gets above 180 and only twice has it hit 210.....and that whas with me being fully submerged in quicksand type mud and keeping the pedal to the floor!

Are you sure its getting hot enough to turn the fan on? On my '87, without using a/c or defrost, it rarely comes on. When I bought the truck the aux fan did not work, and it ended up being a dirty connector for the relay mounted on the left inner fender by the air box. I think I tested it by unplugging the sensor in the bottom driver's side of the radiator, and jumping across the two terminals. That should activate the relay and turn the fan on.