CherokeeClassicWes

So I've had this issue for a very long time and I've never been able to fix it. I first noticed it about 6 months ago and the electric fan was running for so long after I parked that it killed the battery.
I went and got the radiator flushed and I replaced the thermostat afterwards. Still stays on long but eventually turns off. Replaced the coolant temp sensor right on the water pump. Still stays on long, but only sometimes. I figured one more radiator flush might do the trick. But now after a second flush in 6 months the fan stays on all the time after I drive even more often, and now my temp gauge is shooting up randomly and then going back down to add to the confusion. Maybe my radiator is so dirty that it clogged up the new thermostat again?
I really want to take the XJ on some highway trips this summer but I gotta make sure she can handle the heat.
Any suggestions? Am I forgetting a sensor or something?

GreaseMonkey17

Check the fan relay .

Basslicks

Unless there's an aftermarket shutdown timer installed, the fan shouldn't be coming on after the motor is shut off and the key is out of the ignition. I would start tracing the wires coming from the fan and seeing if it's been fiddled with and if you can see any random control boxes or relays in line with the harness.

CherokeeClassicWes

The Jeep was owned by the Forest Service here in Oregon before i bought it so I dont think anyone added anything funky to the wiring for the fan.
Ill check the relay tomorrow, hopefully its just stuck i the on position
thanks!

moparado

What year xj?
Easiest thing to do is to change or swap out the fan relay first if you don't have a multi-meter to trouble shoot.
Also when you did the coolant flush, did you burp the system correctly?

CCKen

Why was the fan running to begin with?

CherokeeClassicWes

Sorry for the late response, I had to run through literally all the options. I took my XJ on a trip recently and towed a small tent trailer, and it overheated. I had to find a last minute rescue on the hiway so that was the last straw with my coolant system being a **** show.
to summarize what I replaced:
-water pump was bad, replaced with new one
-Radiator was just not getting clean of orange gunk, bought a new aluminum 2 row radiator and installed
-bought new hoses
-recently replaced thermo, housing and sensor before all of this
All in all, I think that all along my engine really WAS running too hot and would kick the fan on all the time and kill my battery. Now, after basically installing an entirely new cooling system, my engine runs cooler and the fan never runs when its not needed.
Thanks for the help guys!

freegdr

All that was rereplaced has no effect on fan running after power is turned off.

BlueRidgeMark

All that was replaced fixed the real problem, which was that his engine was constantly running too hot.

Ken got to the heart of the problem, but nobody addressed the question that was never answered. The OP just assumed an answer.

nujeepguy

so if its running hot should we expect to have the fan run, for hours, till the batt dies as he said in the first place?

CherokeeClassicWes

Umm...I'm pretty sure it did...
My engine was DEFINITELY running hot, thus the fan would kick on in addition to the mechanical fan to cool it down.
In addition to that, before I even thought about replacing my entire coolant system I replaced the sensors for the temp gauge and the coolant system. So I'm almost positive that my engine running hot was really the root of this problem and ran my fan all the time til my battery died.
If you have any other suggestions on what might be the cause then be my guest. But it seems that I fixed it already.

BlueRidgeMark

Try to keep up.

freegdr

Once ignition power is turned off fan supposed to stop. No matter what temp engine is at. You got temp under control but fan running all night has not been fixed.

freegdr

No if it does something wrong in its circuit .

freegdr

Never addressed ....