I have a 90' XJ with a 4.0 and i over heated it but the elec. fan didn't come on!!! WTF! So i used jumper wires and the fan does work.

Is there a relay or solenoid or something i should replace that could be gone??

So somethings i should check??

thanks a lot!

 

sorry I can't help you, but I will trade you. mine comes on at the right temp but won't shut off till my battery is dead.

 

haha i think im good. Im probably just going to plug into the harness and make i direct switch to it.

 

Here is how I checked the electric fan system in order of importance:
1) Check the fan by connecting it directly to the battery with jumper wires.
2) Check the fan temperature switch (screwed into the radiator side) by unplugging the wiring connector and jump the terminals on the wiring harness side with a short length of wire. If the fan comes on, the switch is bad.
3) Check the relay (white ceramic on side of fender with two terminals) by jumping the terminals with the fan switch terminals also jumped. If it comes on, the relay is bad.

On my vehicle, the temp switch was bad. Two ways to fix:
1) Replace the switch in the radiator side leaving the factory system intact.
2) Place a manual switch on the instrument panel which makes or breaks the temperature switch terminals on the harness side. This does not disrupt anything in the wiring, fuses or relay circuit and merely replaces the temp switch with a manual one.

I sorta like the manual set-up because you are in control and can use the fan as needed wwithout depending on other devices which may fail unexpectedly.

 

There is a relay, and I can take a picture of the wiring diagram if you would like. If you do a manual switch, you can have it as a bypass for this relay to allow you to turn it on any time you like.

 

If you bypass the relay with a manual switch, you still need a working radiator temp switch. I think the relay is pretty reliable and the temp switch more prone to failure. Jumping the temp switch is no more work and a better fix since you now have a truly manual set-up which does not depend on a working temp switch in the radiator.

 

I just got done fixing my fan problem and it actually turned out to be relay in my case...Tj

 

How did you find it - the faulty relay that is?

 

correct me if im wrong but the white ceramic relay is actually part of the fuel pump electrical system

 

mine did the same thing, i got a toggle switch wired in the cab cause i got fed up with messing with it. you got to jump the 87 and 30 connectors on the relay thangy to get it right

 

heres some pics I am horrible with explaining, btw, the main hole that is in the fire wall is filled with wires from the radio so i couldnt run the wires in there, thats why I used the body/ door jam holes and getto ran the wires.