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Electric fan not working Help! Please!

Sumo2014

NAXJA Forum User
Location
Queen Creek,AZ
Have a 2001XJ my electric fan is not working I’ve gotten it up to operating temperature and no fan. also I believe when you turn on the AC the
fan kicks on and it isn’t I checked the Relay swapped it out with a different one. checked all fuses even unplugged fan and tested to see if power going to the fan and it wasn’t. Is there anything else that I missing or test?
 
2001 the fan doesn’t automatically come on with the ac

The e fan is controlled by the relay, the relay is controlled by the ECM, the ECM looks for 210 degrees from the temp sensor before turning on the E fan

The relay always has + voltage supplied to it — the ECM supplies a ground when it wants the fan to run

Easiest way to check if your fan works is to jump the relay terminals with a fused jumper wire — pull the relay and connect terminals 30 and 87a I believe — 30 should be your incoming 12 supply to the load and 87a should be the + wire feeding the load which in this case is the e fan

Key can be off for this test, to be sure you have power you should probe terminal 30 with a test light
 
2000-01 e-fan runs as already described. An even simpler OBD-II e-fan test is to carefully unplug the Coolant Temperature Sensor on the thermostat housing while the engine is running. The e-fan should turn on in about 10-15 seconds. The Check Engine Light may turn ON, but will clear itself shortly after you plug the CTS back in.
 
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I unplug the the coolant temperature sensor and the fan did kick on.but I’ve let the vehicle get up to operating temperature and even Revved up the motor up to try to pass it above 210 temp which I believe I did from the temperature gage. but the fan still did not kick on. Dose not seem normal. Could it be a bad temper sensor? I also read the codes I did get P0118 engine coolant temp sensor. Assuming that I got that when I unplugged it. and also P1491 radiator fan control relay circuit cleared the code codes ran again but did not get a check engine light again again I’m assuming I picked up that code when I swapped out relays. sorry for the excess information but I just wanted to be thorough and I want to thank you all for your help.
 
If the e-fan runs when tested as described, the system works. 99-01 e-fan does not typically turn on until about 215*-218*. 195*-210* is the normal Cherokee operating temperature. Check again in few days for additional trouble codes.
 
On my 2000 the E fan only runs with the AC on and the air temp over 90 -- Its hard to get it to run while driving, have to sit and let it idle for a few minutes to get hot enough

Honestly I wish it turned on a little sooner, I put a fan override switch on my 96 so I can turn it on when I want it on -- gotta do that to the 2000 too
 
You can get fan temp switches with a lower temp set point.
 
You can get fan temp switches with a lower temp set point.

I think only the Renix have the mechanical/on-off switch. The non Renix engines are controlled by the ECM with input from the CTS and/or the AC unit.
In the first post, the OP said there is no voltage going to the fan. He should trouble shoot backwards from the fan to the PDM including fuse and relay for continuity and voltage as a first step (that is assuming the fan is good).
 
I think only the Renix have the mechanical/on-off switch. The non Renix engines are controlled by the ECM with input from the CTS and/or the AC unit.
In the first post, the OP said there is no voltage going to the fan. He should trouble shoot backwards from the fan to the PDM including fuse and relay for continuity and voltage as a first step (that is assuming the fan is good).

The 2000 doesn't have a mechanical on off temp switch -- temp sender sends info to the ECM then the ECM turns on the fan relay at the proper temp

Also there should not be voltage to the E fan unless the ECM calls for the fan to run
 
The 2000 doesn't have a mechanical on off temp switch -- temp sender sends info to the ECM then the ECM turns on the fan relay at the proper temp

Also there should not be voltage to the E fan unless the ECM calls for the fan to run

My point exactly.

What the OP need to do is to remove the fan relay and jumper across the terminals with a short wire to verify whether or not the wires from the relay to the fan is good. By doing this he will test the complete wire circuit i.e. both the pos (+) and the neg (-). At least for me, that would be my first test.
 
I will add that in that year model range the a/c fan function is controlled by the high pressure switch.
It is easily jumped out at the connector to make it always on when the compressor is on.

This does not address any engine / coolant temp related fan issue.
 
A simple OBD-II e-fan test is to carefully unplug the Coolant Temperature Sensor on the thermostat housing while the engine is running. The e-fan should turn on in about 10-15 seconds, and will prove that the e-fan system is functional.
 
A simple OBD-II e-fan test is to carefully unplug the Coolant Temperature Sensor on the thermostat housing while the engine is running. The e-fan should turn on in about 10-15 seconds, and will prove that the e-fan system is functional.

Sumo2014 said he did that and the fan did not come on (post #5). That is the reason I suggested jumping it at the PDM.
 
Sumo2014 said he did that and the fan did not come on (post #5). That is the reason I suggested jumping it at the PDM.

Sumo2014 did unplug the temperature sensor and the fan DID come on.
I unplug the the coolant temperature sensor and the fan did kick on.

Since the electric fan comes on only when the engine is very hot, 218 degrees and higher, it may not be getting hot enough to activate the fan.
Verify the temperature gauge's accuracy by using a infrared thermometer to see how hot the thermostat housing is. Aim it right at the temperature sensor.

Wiring a fan bypass is easy and the only way to activate the electric fan at lower engine temps.
 
so how exactly would I jump the relay To perform this test? or should I say what are the terminals that I jump. Sorry for the basic question. Ive never done this before. And feel a little uncomfortable doing it not knowing. thank you for your help and all your suggestions very much appreciate,
 
Jump terminal 30 to terminal 87

Terminal 30 is power for the fan, Terminal 87 is the wire going to the fan

Google search "12 volt relay wiring diagram" for pictures of the terminal layout -- the terminals on the relay should also be labeled if you look at them from the bottom

I personally use a fused test wire just in case there is a short in the downstream wiring -- the fuse will blow potentially saving your wiring
 

Yea! I saw that. Now, read the second line in the same post. Am I the only one who have a problem understanding what the OP meant?
 
As Mrs. Thompson always used to remind us before the essay tests: "Proper sentence structure, spelling, and punctuation are a significant part of your final grade."
 
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