Join Date: Jan 2003
Location: Southern California
The best solution is to remove the switch and put all the wires back where they were (by the factory). The fan switch will NOT solve your problem. The fan relay is controlled by PCM (computer). The PCM makes the decision when to turn on the fan and when to turn it off. Get a Mopar relay (don't get non-Mopar parts). Check your mechanical (water pump) fan, the clutch should function in normal operation, if not replace it.. Check all leaks - water pump, radiator, hoses, etc. The water pump should be in good condition. If the coolant is old (more than 2 years), flush it and add Zerex G-05 antifreeze and distilled water (50/50 mix). If you bought a thermostat from someplace else, replace it with Mopar-brand thermostat. I've read many stories from this forum saying that non-Mopar thermostat, especially these "fail-safe" thermostat, is causing problems (overheating, etc). It's best to stick with Mopar parts only.
Last month my radiator leaked, I replaced with many Mopar parts (hoses, clamps, radiator, fan relay, etc). Now, it runs at 205-208 degrees, even during the 100+ degree days, while sitting at idle at red-light traffic. I don't use worm-type clamps for the radiator hoses because they will not "expand" when it becomes hot. I use Mopar clamps, they always expand when it's hot, and shrinks when it's cool. Not a drop of leak using the tension-type clamps.
2000 WJ 4.0L, drop-in K&N filter, Addco rear antisway bar, Bridgestone Revos, Overhead DVD monitor w/ wireless headsets.
2007 BMW 335i, Montego Blue with Lemon seats, premium & sport package.
2004 TJ Sport 4.0L - SOLD :(