Just like the title my electric fan does not come on. I know it works cuz I hooked it strait to the battery and it came on and I know it's not the relay cuz I swaped it with a working one and still nothing. What else can it be? It's a 2000 4.0 sport

 

More details needed... what are try doing that should make it come on? It won't kick on for heat until about 220* I believe. And it will come on when you have your ac on as well. Turn your ac on, see if the fan works, report back,this is of course assuming you have ac and it works.

 

On 2000 and later models the electric fan is controlled only by the engine coolant temp sensor. 213 degrees is the magic number. 1999 was the last year for the AC activating it.

Do you have the full gauges or dummy lights? Does the temp gauge work?

In the PDC there is a fuse and a relay for that fan. Swap em out

 

I did swap out the relay and I have actual gauges but it sits slightly below 210 due to my 180 dagee thermostat

 

Okay... 180 degree thermostat in February and you're wondering why your auxiliary fan isn't coming on...? There's supposed to be a 195 in there btw.

 

I know I swaped it during the summer cuz I don't think the fan worked than either but I think I'll swap it back

 

The AC system in the 2000 and 2001 XJ still operates the radiator electric fan, in addition to the ECT sensor.

Here's some reading for you that will explain, in a round-about manner, how the AC circuit works. The difference between the 2K & 2K1 system and the 98/99 is the introduction of a new Dual Function High Pressure Switch.

http://www.askamechanic.info/askamec...nt/view/73/47/

With or without A/C request the electric fan will come on only when the
coolant temperature is at least 223° F, and will remain on until the coolant temperature drops to 217° F or below. Regardless of coolant temperature.

When air conditioning system pressures reach 300 +/- 20 psi the electric fan will engage and continue to run until the A/C system pressure drops to 235 psi minimum, then the electric fan will shut off.

 

Thanks for clarifying, I knew I didn't have a MAC certification for nothing.

But, as stated above,with the ac on,the fan should kick on, friendly on what the temp is where you live, you may have to try it in your garage offer wait until it gets warmer. The is nothing wrong with running a colder thermostat, but195is factory, and will keep the engine colder/possibly keep the fan from coming on unless it's a hot summer day and you are stuck in traffic.

 

Here's a procedure for testing the engine coolant overtemp setting that would engage the radiator electric cooling fan.

I've read several statements on several forums that if you simply pull the connector off the ECT the fan will run. This serves no useful purpose when it come to determining if the PCM sees an overtemp signal from the ECT sensor, besides it trips a P0118 CEL and requires resetting the PCM.

Even though you may see around 235* on your temp indicator during the test, the PCM will have seen its target temp to turn the fan on and did so.

The test requires the engine to be running so the alternator is on line. The radiator fan relay control coil requires the engine to be started and running (Start-Run bus) to get power from fuse F10 in the Junction Block. When the PCM senses a signal from the ASD relay it knows the electrical system will handle the fan load. When AC is requested or there is a coolant overtemp signal the PCM provides a ground to the fan relay control coil. The fan itself draws from the Batt bus, and is protected by a 40 Amp fuse in the PDC.

This procedure is tried and true on my '99.



Several months ago I was sitting in my driveway idling my XJ when heared/felt my electric fan kit on so I looked at my coolant temp indicator and saw that the temp was 220*F. The fan continued to run until the coolant temp got down to around 210*F then it cut off. Coolant temp stabilized at just under 210* (indicated) from then on. I still don't know what caused it to climb to 220* to begin with. A sticky T-Stat? It hasn't done it since.

 

Hmm I got the temp wrong. Just for documentation's sake this is from the 2000 XJ FSM page 7-9:

1999 XJ FSM page 7-8:

So my understanding based previously on other people's posts was a bit off (big surprise!) but the two do operate differently. Refrigerant pressure switch in >2000 vs. compressor engagement in <1999