1999 Jeep XJ Electric Cooling Fan Problem & Solution

Last Winter the heater core failed in my 1999 XJ. I took the jeep in & had the AC system discharged so that I could pull out the dash & remove the core. However, I soon found out that the Auxiliary Electric Cooling fan had stopped working. It worked just fine before I had the AC de-pressurized. So, I recharged the AC & now the Electric cooling fan works as it should.

[@joesussex4856]

Thanks for showing that trick to manually turn the fan on with defrost setting, that kept my engine cool enough to make it to my mechanic.

[@jonkitrel6622]

I thought that my electric fan cycling relentlessly w the Def on was something l needed to troubleshoot... it's "normal"!
You just saved me a boatload of frustration!

[@thomaschiappisi3726]

thanks for the manual check of the fan & adding the AC factor to the fan malfunction!! Good Info!

[@dallasyarbrough]

Thanks for the video! Recently buy extra he started overheating for no reason they couldn’t figure out why. I have a Killswitch in my jeep that whenever that is on that fan would start, and don’t ask me why that is how the previous owner wired it up. So I did all of the test that people have said in the same show that the fan should be dead but every time I did a Killswitch it would start up. I started looking under the hood and somehow one of the ac lines got disconnected! Easy fix now!!

[@markgabello58]

They just changed my 2001 water pump for my Jeep Grand Cherokee Limited and I changed the fan relay that's underneath the passenger side front headlight and I did the modification of just cutting a hole in the plastic seems like I just tried that myself I had a heating issue problem with my fan I'm not sure if a rodent got in there and cut a wire but it seems to be working I just tried what you did thanks

[@jalatecompa]

hi my fan never stops even on cold start as soon as i turn the engine on it starts to spin, new relays been replaced

[@nightcrawler6723]

I would try unplugging (temporarily) the coolant temperature sensor, the one mounted on the thermostat neck. If this stops the fan then maybe the thermistor is bad or has some how shorted to ground.

[@dadirtydawg7789]

@@nightcrawler6723 where is the ground located?

[@khndenmark]

Hi I have a xj 1999, my fan kicks on as soon as I start the engine and then it’s stops after maybe 10 seconds and then it starts again and so on, until I stop the engine. Do you think there is a problem or is it the right way for the fan to operate?

[@nightcrawler6723]

This sounds normal.If you have the Heater/AC control on any AC modes the fan & compressor will cycle together. Also, in the Defrost or Defrost/floor mode the fan & compressor will cycle on & off together. I don't know the exact temperature that the electric fan will come on and stay on. But on our jeep it stays off up to 210 degrees and will be running constant any time it gets over that temp. Usually, on a 100 degree day that jeep will run at a steady 215 degrees.

[@aesa3628]

It's normal

[@khndenmark]

Ae Sa thanks for your answer

[@mealticketscrub2561]

They changed that in the 2000 and 2001 models. It no longer turns on when u turn on defrost. Mine is a 2001 and the electric fan only turns on when my temp goes past 105 degrees celsius

[@nightcrawler6723]

Oh, good to know thanks for the info.

[@judyvanover5173]

What if the ac has never worked can u still use that method?

[@nightcrawler6723]

Probably, you should try it on your jeep and see. Usually, in defrost mode the compressor will cycle on and off with the fan. This is supposed to help keep the compressor seals from drying out.

[@toddellis5197]

I realize this is an older thread... Your info just may be what I need... May I pick your brain a little... Imagine I've tested all the good stuff.... Fan runs with jumper, fan runs when i disconnect temp sensor, but fan does not come on with AC, or on defrost. Fan also does no come on with jumper on pins of the AC accumulator...... Well, shit, I think I may have just answered my own question, lol...
But what do you think?

[@scottgrigsby4210]

your fan is controlled in 2 ways, the high pressure switch and engine temp, temp has to be 218 for it come on

[@SJD_MEDIA06]

I’m trying to figure mine out mine won’t come on at all and my jeep keeps getting too hot in traffic

[@pat86able]

A/c compressor runs on any vehicle when defroster is selected...

[@nightcrawler6723]

No, not all vehicles have a/c.

[@ralphnabozny8494]

its all complicated, running off a compressor pressure signal. i have a 92

[@nightcrawler6723]

Hey, Ralph I have a 1992 XJ (4.0L, 5spd) as well. I have maybe one video featuring that jeep. I really love that old school jeep.
I did a video on a fuel pump replacement and I did some trailer plug re-wiring.