On my 97 XJ 4.0 I have replaced the water pump, radiator, fan clutch, thermostat, water temp switch and new electric fan.
My fan will come on if I jump term on fan relay, but it will not come on during driving.
My A/C does not work, and I have no plans to make it work any time soon.
This jeep is our backup vehicle, and I am trying to make it reliable without fixing every little thing, just reliable.

So I found a cooling fan wiring kit that has everything needed to run new wires to the fan but my question is there a 3/8 port somewhere that I can use to run the new switch that will turn the fan on and off at a set temp?

I know of the one next to thermostat, but I would like to find another source if possible.

 

Are you putting it in a situation where it should come on during driving? I don't think the fan comes on till 218°F, or something like that.

Fan should still come on if you put the HVAC to AC, even if it doesn't work, as long as the circuitry is still there.

If the fan works when you jump the relay, why would you rewire it?

 

You didn't remove the factory mechanical fan did you?

 

The factory electric fan only comes on in regular driving when the a/c or defrost is on. If not using the a/c or defrost then it won't come on till 220 degrees.

 

He mentions a new fan clutch so I take it that's a no

Mine didn't even at 105 or 106C at some stage (221-223F) but works fine bypassed.
Probably a 97-only thing 😖

 

I completely missed that

 

Your jeep needs to be fairly hot for fan to turn on via the thermoswitch that is on the thermostat house. The dash gage will be a bit over the half way mark before that switch turns on the fan automatically.
If that aint working, suspect the thermoswitch or its connections are at fault. If you get the engine good and hot with dash gage well over the center mark, you can ohm test that switch to see if it closes or not, if not, well then the switch is bad. likewise you can test its wires by removing the switch connector and jumpering the two terminals on the connector with the ignition on, and then the fan should turn on, if not turning on when jumpered, then there is an issue in the wires. this switch triggers the fan relay. make sure all the connections to that relay are good also.

I added a manual override toggle switch on my dash to turn on the fan when I want by adding the toggle switch in parallel to the thermo fan switch.

As others stated, the fan should turn on when the ac is requested, it takes its on signal from the ac compressor clutch signal as I recall.

 

In 97+ , the aux fan should come on when the connector at the thermohousing is disconnected.

 

Thanks everyone for your help on this one. My A/C does not work and I read on one post that you have to have head pressure on the compressor
in order for the fan to be signaled to come on, well as above poster said just turn on your A/C and it worked. I had to cycle thru all the settings to find the on that would work but I was excited to see the fan working with the engine running.
I took it on a good long ride and she stayed steady at 200 deg.

Thanks everyone

 

So despite your A/C not working, turning it on an A/C setting makes the aux fan work?

 

No, the compressor clutch needs to engage then the aux. fan will come on.

 

Thats what I understand, but I want to hear from the OP if that's what they meant

 

If you jumper out the -fan on- pins in the high pressure switch connector the fan will come on whenever you choose an AC mode, without having to engage the compressor. I will post a picture of what two pins tomorrow.

 

Interesting - are you suggesting it to work like a remote aux fan switch like that then, using the A/C selector instead

 

Yes exactly...BUT it easiest if you dont have a working ac so the switch connmector is available to jumper. If you have a 200/2001 then you would have to splice into the wires for that leg to keep the connector attached if your ac is working