I have a 1998 Jeep Cherokee w/4.0 6-Cyl.
The Jeep has been overheating. I have replaced the Thermostat, Radiator Cap, Temperature Sensor, and flushed the coolant.
I have noticed the Aux Cooling Fan never comes on. I tested the fan by jumping it and it works.
Next on my list to replace is the Coolant Temperature Switch. However, I have no idea where it is.
Can someone tell me where to locate this Temp Switch? A picture or diagram would also be a great help.

Thanks.
Rob C.

 

Wow, talk about a small world...
I have a 99 JGC w/4.0 six cyl that's overheating.
I pulled the thermostat and tossed it into some boiling water and noticed it barely cracked open. In addition when I had the motor running prior to removing the stat I noticed the fan was not kicking on even when the temp went to 240. I was going to jump the fan to test but I just moved and dont have the xtra wire so I was getting ready to head up to the auto store for the stat and some wire. I decided to check the internet for any other possible issues and ran across another discussion about the radiator fan switch relay.... there is some good info including where to find the switch and a "how to" replace on this link: http://rigs.corequipment.com/cebby_W...ling.htm#relay Hope this helps someone else too.
*btw*
I'm Rob C. as well.....

 

Wow, a cooling system thread started 5/10/10 and just now gets a response? Oooops! Efan should come on +/-218F OR when the a/c compressor is engaged OR when the coolant temp sensor is unplugged/ignition on. The sensor is in the t-stat housing.

 

Ok, for the purpose of troubleshooting, can we assume that if you unplug the coolant temp sensor turn the ignition to on and the E-fan does not come on that the problem is most likely the fan switch? (provided the e-fan is good)

 

I believe there is also a fuse/relay for the efan in the black box under hood (passenger side).

 

Yes there is, (1) 40amp. And if that is good as well doesn't that pretty much leave the switch as the faulty unit?

 

I know this thread is old..... But the question about where the fan switch is located and no one has yet to answer. I have 2000 jeep cherokee 4.0L and has the same problem as the guy generated this thread. I replaced cooling relay, cooling temperature sensor & checked fan good.

Most posted thread I read about fan not working was that after replaced mentioned above and fan still not working. Next step is to replace fan swith.

So, if someone know where the fan switch is located and could reply, it is greatly appreciate.

Thank you,
Gerry

 

The switch is on the back of the head, on the intake/exhaust side, after the last stud that holds on valve cover. I'll take pic if needed

 

The actual "switch" is built into the computer. If you disconnect the sensor connector in the thermostat with the jeep running the fan should turn on. If not then the fan or relay or fuse or computer is bad. On a 98 the fan will come on if the ac is turned on AND the clutch actually engages...if there is low freon pressure and the clutch does not engage the fan will not..i think the fan relay and the ac relay are the same so they can be swapped for troubleshooting

 

Hey, folks? This thread is TEN YEARS OLD. I think it's time to let it rest.

 

To help those who are looking at this thread ... If you car is over heating another thing to check is the oil level. Ensure the oil is full. I replaced all the cooling items and was still having the car temperatures slowly move into the danger area and realized my engine oil was low ... it made that much of a difference in the 100+ temps.

 

Any way you can take a photo of the location?

 

If your XJ is a '98 it won't have one here.