A/C and aux fan issues

I have searched and googled to no avail. When I purchased my XJ a few months ago it did not come with an aux fan and the a/c didn't work. It didn't bother me because it was cold. Now that it is warming up the jeep is running hotter and it would be nice to have a/c.

I went to the junk yard today and grabbed an aux fan. I plugged it up and cranked the engine. The fan runs constantly. If I turn the key off though it stops. While running if I pull the relay, it stops. If I pull the temp sensor though it continues to run. When I plug the temp sensor back in it stops for a sec, then starts running again.

Now with the a/c, when I turn it on it will not engage the fan clutch. I can use a jumper wire to the compressor and that will engage the clutch so I know it isn't an issue with the compressor. I can pull the relay and use a jumper wire to the fuse box and it will engage so I know the wiring is good. It doesn't blow cold either so it may be low on refrigerant. Do these jeeps have a sensor that will disable the compressor is low refrigerant is detected?

I am beginning to think the two issues are related. Any ideas on where to start.

92 Cherokee Limited AX4 190,xxx miles.

There is a low pressure cutoff switch. You are likely low on refrigerant. Don't know about your 92 but my fan ('88) won't run unless the compressor engages.

Bad news is that yours may take R-12 which is very expensive. If you do take R-12, you may wish to spend the money to convert to R-134a. You should also check for leaks.

Only way to tell is to get a set of manifold gauges and see what pressures you get. I would recommend you either find someone who knows what they're doing and has the tools or take it to a shop.