2000 Cherokee 4.0. i replaced the electric fan. took to mechanic, he said it wants to engage but does not. said its ac hi pressure switch or needs new ECM. it runs fine while moving but when idling it overheats. tired of sitting on the side of the road any ideas?

 

verify voltage with a multimeter at the connector of the electric fan when it suppose to be the spinning. if you have power at that moment most likely your fan is bad.

marc

 

thanks. i put a new fan in myself, lol. when it didn't work i took it to a reputable shop. now its back to me, lol.

 

Should not need aux fan when at idle. Mechanical fan might need replacing. Aux fan only comes on when ax pressure gets too high or temp goes above pre set temp.

 

Disconnect the fan and jump it directly to the battery. If it spins strong, its good. The fan should also turn on with the temp sender in the t-stat housing disconnected. Overheating at idle could be the fan clutch, and/or the cooling system needs serviced. When was it flushed last? Any leaks? Check the coolant level, etc..