tonybeirut

Ok so i read all the e-fan problems and did all the tests required but the fan works for a while than stops.

Sensor test (fan sometimes kicks sometimes not)
Fuse changed then external fuse installed (fan kicks for a while than stops)
relay changed than external relay installed (fan kicks for a while than stops)

"Attached are photos for the external fuse and relay."

The efan kicks if i run a wire from the battery to the relay (then remove it) but after 10 15 minutes it stops, every time i run that wire it kicks.

The electrician said the fan motor, sensor , relay, fuse, are all working but something wrong in the computer (attached is a photo) , it doesn't give order to the e-fan to kick when temp is high nor when AC is switched on.

And by the way i changed the engine fan clutch, new water pump, cleaned the radiator, new water hoses, new radiator cap, trying to fix the fan problem without success.

Shall i change the computer? (i pray not )
Anybody had the same problem on his jeep and fixed it?
Please help im desperate, this is my 1st Jeep ever bought in my life...

*The Dude*

What year is your xj? The fan wont come on with the a/c right away on some of the newer xjs. Like 99 to 2001. The computer turns it on if the high side pressure switch reaches a certain level but that sometimes takes a while to come on. The dealership can program that out and have it come on instantly but most aren't done that way.


As for the rest of the tests you've done, the concern is that the fan will come on but then stops. This makes me think you have a bad fan motor. Some of the fans I replaced did this exact thing. The fan would come on but would just stop when it got hot.


Try bypassing the relay and running power directly to the fan. It should run until you pull the jumper. If it stops, bump the fan shroud housing and see if it tries to start back up. I usually just check the voltage at the connector and if its got voltage and the fan doesn't work, I put a new fan on.

*The Dude*

Also, if you find that the fan is working and its the computer, just wire in a relay to the ignition to come on when the vehicle is running. You can also put a switch on to shut it off if you cross a puddle or two. lol

sycoglitch

First. What year, engine, transmission, xwd, is your jeep. Information helps. Later year jeeps don't run the aux fan with the AC

Second, what are you considering high temperature

tonybeirut

My XJ is a 1994 Country. The fan is working great when i run a power directly to it and it also kicks when i run a direct wire to the relay , i just did both test again 10 minutes ago. Any other tests i Should do?

tonybeirut

Any detailed photos for that please?

tonybeirut

Its on my profile XJ 1994 Country, 4.0 L, automatic, 4wd,
High temp is 110 Celcius (230 f)

sycoglitch

The crappy mobile site dont show certain Ingo. It sucks royally. There's 2 temp sensors iirc for your year. Not sure if you checked both. There's one at the back of the block too

*The Dude*

OK....I think on a 94 the cooling sensor is in the radiator. Is that right? I had an 88 back in the day and wired my cooling fan on a three way switch so that it could come on when told to by the sensor and when I wanted it too by the switch, and when off it wouldn't come on no matter what for puddle jumping.


If your 94 is like my old 88 removing the connector on the sensor wont make it come on if its wired the same. I think the best way to test the system is to remove the connector at the sensor and check for voltage. If the 94 cooling system is like my old 88, the computer doesn't do anything to control the cooling. It is a closed self contained wired system. Ignition runs power through a fuse to the sensor in the radiator. The radiator sensor closes and lets power energize the relay and then the relay sends power to the cooling fan.


I'm trying to find a schematic for your exact year to see exactly what system you have. The afore mentioned is better than computer controlled.


UPDATE: I found a schematic that shows your 94 is controlled by the ECM. That changes everything....ugggg.

tonybeirut

Are you sure there are 2 temp sensors on HO engines? i couldnt see that, maybe a photo to show me where pls

tonybeirut

Nope the sensor of the 94 is on the thermostat, removing it will kick the fan in normal case (after 6-7 seconds) , mine is not doing that unless i jump a wire to the relay for about 2 seconds, then the fan will continue running

sycoglitch

I know on older 4.0s there was 2 stats. I wish a remix guru would pop in too confirm.

Now another question. You say you engine gets to 230f. When does this happen. Driving, idling, traffic crawling etc. Maybe we can fix this issue too at the same time. Have you done any cooling work

*The Dude*

Ok...I found the schematics in this older thread.


https://www.cherokeeforum.com/f2/ele...rature-145386/


The schematic shows the relay being controlled by the ECM on the ground side. If you jump the relay to a ground on the ground side and the fan comes on the circuit running the fan is good. That just leaves the wiring from the computer to the relay in question.


To check that you can remove the connector at the computer and pull the relay and see if you get continuity between the relay and the pin on the connector. You should get good continuity. If you don't, then you might have a burnt wire from the computer to the relay. If you do, then I would check the pin in the connector and the ECM to make sure they are clean and not loose. Maybe spray the connector with air and use a light wire brush and spray with air again.


If you find all that is good you might then have a bad switch in the ECM...uggg.

tonybeirut

Yes it use to get hot in traffic. I changed everything to make it run cooler. Fan clutch, water pump, water hose, removed and cleaned the radiator.
The efan problem not kicking is caused by Somthing electrical for sure coz it's working when jumped from the battery to the relay. Maybe that problem occurred after I run over a water hole last week and the under car was splashed with water.

*The Dude*

Oh...and if you do find that it works with jumping the relay, and you think its the switch in the computer....


Run a source hot wire off ignition to a switch in the cabin. Run from the switch to a relay in the engine compartment. Ground the relay on both grounds and use the power from the switch in the cabin to energize the relay. Then use the feed from the relay that will be grounding to ground the fan relay. Now when you turn on the ignition and the switch is in the on position it will energize the relay that sends a ground to the fans relay energizing it to turn the fan on. When you want you can turn the switch off turning the fan off. The fan will run all the time with ignition on unless you have the switch turned off.


Also, you might want to look in the plug in for the relay and make sure the connectors are all tight. I haven't found one loose but can't hurt to check. I have found a ECM pin loose before so check that one for sure.


Hope this helps....