I just purchased a 2000 grand cherokee with a 4.0 motor and 137,000 miles. The temperature gage seems to reach 210 really quick. Coming home today it seemed to be running hot in traffic with the a/c on. I have read several posts and can someone please clarify something. The electric fan was not running with the ac on. Should it turn on immediatley when the a/c is engaged? I have seem post state it does not come on immediately the temperature has to reach 218. It did not overheat, but i dont want to risk it, i have slow commute with alot of time in traffic. Is there a fuse for the electric fan? All if have right now is the owners manual, and i dont see a fuse for the fan. Any suggestions on what i can check or how i can check to see if the electric fan is functional. I also have a 1990 and it does not run hot, even with the closed systems. Any help would be appreciated. Thanks

 

Yes with engine running pull the plug out of the temp sensor, " it will be on the thermostat housing" the fan should come on immediately. At least that's how I checked. If it makes u feel better look up a write up on how to run a switch to the fan so u can turn it on as you please....also I hate to be the bearer of bad news but 00-01 models came with a 0331 casting cylinder head, its notorious for cracking.Trust me I have one. Just wanted to let you know so u can keep an eye on it

 

I unplugged the temperature sensor and the fan did NOT come on. does this mean the sensor is bad. Also the check engine light is now on. I restarted it a few times and it did not go out. will this reset. I have a 1990 xj as well, i wired a switch to the fan, so that was the plan for the 2000 even before the issues. thanks for the info.

 

It's not the sensor, could be the relay or the fan motor that are bad. The light will reset after a while and so many "trips". Hot wiring the fan may set a check engine light every time you flip the switch.

 

Disconnect the battery for a half hour, light should go off. As far as fan check relay,run switch if none of that works fan motor is bad
But I did run a switch to my fan and the light never came on, just make sure to run a inline fuse... I don't know if it was OK to do but I just spliced into the blue wire running to temp sensor with the positive wire from a switch I already had installed that wasn't being usdd, it has a inline fuse also. Again I do not know if that was a good idea I only use it when at a stop when hot outside but iv had no issues yet.

 

BTW mine did come on at 218 I know that's normal but for piece of mind I wanted the option to cool it off as I liked. It still works with sensor to

 

Thanks for all the info. Im trying to search all these post while at work. Can you tell me, or is there a post on how to test (jump to the battery) the fan to see if the motor works. Is there a way to determine if the radiator fan relay is bad. The relay under the hood looked good, and i didnt see any blown fuses, but how to you test the one under the headlight. Thanks again

 

Well u could pull a fuse the same size like the ac cluthch fuse and plug it in the cooling fan fuse then pull the temp sensor on thermostat housing and c if it kicks on granted the fuse u swap is good. Other than that sure fire way to tell if fan motor is good shave a lil ruber off the blue wire exposing the wire run a piece of wire to the positive battery terminal and do the same with black wire to negative terminal.. Be sure not to touch the two bald wires together. When done make sure to tape over where u shaved well.
I'm sure there is a more technical way to do this but that's just what iv always done. If u do that and fan doesn't come on your fan is bad for sure

 

BTW I pulled my sensor today just to c if engine light would come on, couldn't remember of it did when I was where u were at. And I did I assure the light will go off if u disconnect the battery a while. Additionally I have better luck searching Google and typing the keywords to question fallowed by xj
Usually brings up the Cherokee fourm post and others from naxja ect. even YouTube videos.

 

From what I've read, the electric fan does NOT come on immediately when the AC is switched on.

After the AC has been running for a little bit, the fan should come on. I believe the AC has to 'pressure up', which then activates the switch.

I watched mine yesterday and with the AC running I believe it took about 15 seconds to come on.

 

yaah, its not coming on at all. I tried for 15 minutes letting it get hot and I never saw it come on to cool or when i switched on the A/C. Im going to jump the fan tonight and see if I can make it come on. if it works the next step will be to test the radiator fan relay under the headlight. thanks for all the input, ive only had this jeep 5 days but it seem like they all have cooling issues.

 

Yes it is a labor of love

 

thanks everyone, the radiator fan relay under the headlight was bad. just cut a hole in the plastic and replaced.

 

Hmm that's weird. On my 98 as soon as I turn the *** to AC and the clutch engages the e fan comes on. Strange.