aux fan/ac

i have a 99 cherokee sport and when i got it the fan worked up untill about 2 weeks ago. ive been thru countless threads and i have not seen an answer unless its a broken wire witch who knows where to start. well i changed my relay and no dice. i jumped across the relay terminals and the fan operates as dose the ac clutch but i put the relay back on and nothing even after reaching about 220 230 degrees. ac is on and pump dose not run unless i jump the relay terminals. i know when the ac pump is on the fan should run but i cant get either to run with the relay in. any help is appreciated. just wana get my check engine light off. thanks a bunch.

There are two relays, one for the A/C Clutch and the other is for the Aux Fan. If the A/C clutch pulls in and the Fan does not start, then the fan relay is suspect. You have proved the fan motor by jumping the relay out of the circuit.

When the engine is running, pull the cts plug at the t-stat housing, and the fan should kick on w/in 3 seconds.

WHredcheif said:

i know when the ac pump is on the fan should run but i cant get either to run with the relay in.

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Not in your case. It comes on after a certain ac refrigerant pressure, iirc. Not based on when you turn the AC on.

I would test the other side of the relay socket and see what you get.

That happened to mine and it turned out to be the ac condenser was low on refrigerant. I charged it and it worked fine. Hope it helps.