Hello! I recently bought a 1996 Jeep Cherokee that had been sitting in someones garage for years and decided to fix it up. I've got it running great (no stranger to car repair) but there's just one thing I can't figure out. The electric cooling fan isn't coming on when the Cherokee reaches 218F for some reason so it just continues to heat up at idle and I really don't like that. It has the high output 4.0L so the coolant temp sensor is on the thermostat housing, I replaced that in hopes that was the culprit but nothing! I also replaced the aux fan relay with a new one and it has new coolant. So I removed the cooling fan and applied 12V directly to the connector annnd it works! BUT when you put it all back together no cooling fan. So I did a ton of fiddling and found out that while the jeep is off if you unplug the coolant temp sensor and then plug it back in THEN start the car up the cooling fan kicks on only once but as soon as you turn it off and then on again...nothing. Also if you unplug the coolant temp sensor while the car is running the cooling fan stays on (as does the CEL). I looked around and found that this means typically that the cooling fan control module is bad but from what I gather this era of Cherokee does not have one, it's built into the fan itself? So my next step is to buy a new electric cooling fan but before I waste anymore monies I'd like to ask the professionals what they think lol. Any help is much appreciated!

1996 Cherokee 4.0L HO Automatic with CommandTrac 4x4

As a side note if you unplug and plug in the cooling fan relay the fan comes on for a split second and then quits...so confused

 

Man I have been having the same problem on my 2001 Jeep Cherokee, the electric fan doesnt seem to kick on when I turn the car off and all the residule heat just stays in the engine so when you get back in and start it up its overheating right way until i get moving down the road. Do you think I should start with the thermostat, i'm on super tight budget trying to troubleshoot this but cant afford to waste money changing everything. Will a scanner tell me if I need to replace the relay or therrmostat? This was my grandpas jeep in CT and ive been driving it in TX last thing I wanna do is blow a head gaset. Any advice would be greatly appreciated

T

 

The cooling fan is not supposed to turn on with the engine off in a cherokee

 

I got the fan working now but the engine still seems like it has to much heat in it after I go for decent drive and then turn off and then back on again shortly, any ideas on the best solution? I’m seeing everyone installing a bigger radiator but I kind of want to keep everything factory like when my grand dad bought new. I’m running at a solid 210 but it seems like it’s a lil too hot. Thank you for responding also

 

Man I have the same issues and just wrote up a thread asking why my fan won't kick on after the car runs at idle for many minutes. I installed a new t stat. I currently am having issues with the neutral safety switch and need to replace that. I also installed a new blower motor and a JY blower motor switch. For some reason, no air comes out whether cold or hot. So I have my issues. I will be reading this thread to learn from it and apply to mine.

 

210 degrees is not too hot. if it is running at 210 degrees, it will get hotter when you turn the engine off. That's how it works. When you start the engine again, it will cool down and stabilize once the cooling system circulates the coolant.

That is assuming that everything is in working order.

 

mine stopped working, I bet there is a fuse, the horn is also not working, I will check the FSM asap and update

update;

so my '96 FSM mentions fuse 15 & 18 and there is a relay

I will do the usual thing and check both tabs of EVERY fuse with a test light, starting with the PDC

the ones under dash, I use a phone torch and mirror, bit tricky but done in 10min

take a digi pic of any fuse before removing it

I have only one hand working atm, so hopefully it is just a fuse

 

There are many different years mixed into this thread...pre 96 ...the temp gauge is driven by a separate sensor at back of drivers side head. It ONLY drives gauge and may not register same temp as the coolant temp sensor in thermostat, which turns the fan on. The fan should come on APPROX 217-222, or when the ac is turned on.

96...a mix year...may or may not have sensor back of the head....other fan functions similar

97-99....all temp gauges and fan functions come from thermostat sensor...fan comes on with any ac mode

2000-2001...fan is TEMP driven only. Ac has no effect unless you jumper out the fan driver of high pressure switch. These years turn on at slightly higher temps than earlier

ALL ABOVE will turn the fan on if thermostat housing connector is removed..throws a CEL code and light

 

There is no control module in the aux fan. It's managed by the pcm and should come on either with any AC setting (cycling) or when your temp reaches 105 C (221F) or thereabouts (constant) untill the temp is back down (to a certain threshold which I don't recall.

Currently I'm driving around with live data because my temp is going up at idle and I suspect a headgasket issue.
The ECT reaching 106C (223F) and towards 107C but my aux fan doesn't come on. AC is not working but aux fan does come on when you unplug thermostat ECT sensor. This is 97+ however with the one sensor
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