Aux. Fan on a 2000

Should my Aux fan turn on when the AC is on?

And what are the parameters for when it should turn on. I think my relay is Fried but I can't be sure...

On my 2000 the E-fan only turns on in relation to the temperature on the dash gauge, AC/ on or off doesn't matter. It comes on at about 215-218*. A replacement relay is cheap enough, buy on if you are worried.

Ok I will check it to night and buy one tomarrow if needed thanks...

You can also run a switch to the dash very easily if you're worried about overheating. It's quite simple and only takes a few hours at most. I used the alternate power source (like the 12V lighter) in the dash on the left.

while the jeep is running, unplug the coolant temp sensor. if everything is working properly the fan should come on in a few seconds. this will, however, turn on the MIL light. it's a great quick test of the e-fan system though.
also, for your model year, the fan only comes on because of temp. the ac alone won't turn it on.

kf_chris said:

You can also run a switch to the dash very easily if you're worried about overheating. It's quite simple and only takes a few hours at most. I used the alternate power source (like the 12V lighter) in the dash on the left.

Click to expand...

BE CAREFUL if you decide to wire up an Alternative power source for the Auxiliary Cooling Fan....; The 12V is constant when the ignition is on...; the ECM controls a switched ground to energize the fan...

You will need to cut the ground lead to the fan, install a Bosch cube relay that has the terminals 87 and 87a so you can switch the ground from normal to alternate ground to start the fan. Run a 12V power source and toggle switch to energize the relay... and you are set....