strokerspeed

Recently bought an 89 xj, just to have some fun with, never had one

I now notice the electric fan is ALWAYS on, from the second I turn the key to "on" (before starting) until I turn the key off. Actually seems the mechanical fan is always on too (need to drive more to be sure of this, but does come on as soon as engine starts), but I'm not too worried about the mechanical fan, I can just replace the clutch on that one. The electric fan though...gotta stop. Jeep won't even get to 210 idling (runs good )

I'm guessing it could be the diagnostic system is in test, I know most systems (when wired for diagnostic testing) trigger the fan to run all the time...do XJ's do that? If so, which are the diagnostic wires/harnesses?

More likely, coolant temp sensor...? But where is it not coming off thermostat housing...

Maybe the fan relay?

Where should I start here?
Thanks in advance for any help/information!

strokerspeed

No help?

I got a new relay, went to change it and realized the harness was fried. So I cut it out and put on connectors. Tried the old relay and new relay, fan still always on...?

Seems as though some not so professional wiring may have been done down a little further towards the headlight from the relay, I'll take pictures soon

On a good note, just took her on a 600 mile trip and she ran great! Fan on the whole time but runs great

Bux91XJ

You are looking in the right spot. I have a little jumper wire I can put in place of my aux fan relay that makes my aux fan stay on all the time. I use it when wheeling in hot temperatures. I'm betting your wiring going to the aux fan relay is shorted somewhere.

strokerspeed

It looks like it is jumped to be on, looks like paperclips...

two wires going to a green harness, then rigged to paperclip type metal and electrical tape around the custom work, lovely

I started the jeep (fan on as usual, went and pushed that thing down to see color of wires and bam the fan went off, then on, then off, so yea its definately rigged. How is it suppose to be? Check out the pics, what should I do from here? Thanks!

Slick761

Theres a temp sensor (switch) with two wires coming out of it on the tank on the radiator in front of your air box. The connector on the wires is supposed to connect to the wires that were jumped in your jeep.

sthon

I would be wondering why the PO wired the aux fan to run all the time. When you do get it figured out keep a close eye on your temps, that very well could have been the PO's band-aid on a cooling system in need of maintenance.

Slick761

It's a renix... It probably overheats.nothing a good flush and a new pressure bottle won't fix. I love it when people "fix" problems like that.

strokerspeed

PO said he replaced high pressure bottle about 15 months ago (looks new), but ya not sure if its going to overheat or not.

which tank are you reffering to?

ok, I'm goin to wire in a switch in case it tries to overheat on me (also for slow dirt roads in the future).

djb383

The switch is a band-aid covering up something else that's causing the overheat. Solve the real overheat problem and let the ECU operate/switch the efan on/off automatically. The switch solves the problem of the fan operating in high water crossings, it doesn't solve the overheat problem, just band-aids/covers it up for a while.

Slick761

The ecu doesn't control it, its a simple temp switch in the radiator. Like I said the temp switch is in the side tank of the radiator in front of your intake. You don't need to wire in a switch as stated above because the fan will turn on when ur gettin hot ( a little above the 210 line) flush the system and you won't have a problem.

strokerspeed

Alright so I took out the paper clip rig and plugged the temp sensor back in. Been driving it in 75-80 degree weather in town with no problems. Fan no longer runs until temp gauge says about 200. I'm guessing my temp gauge is off and its really 210 when its kicking on, but either way, not overheating, running pretty good.
About the only thing I would complain about, is after getting the fan working properly I took it out on the gravel roads and well "jeep" roads to make sure it didn't overheat in extreme conditions, it never got close to overheating, but every once in a while when I would come to a stop it would high idle, around 1500-2000rpm, didn't matter weather I was in gear or if I put it in neutral, it would stay high idle. It would only last 10-20 seconds, but its not right...
I've replaced both ccv hoses coming off valve cover...inside the valve cover had lots of gunk , or at least where the hoses went through. Other than the high idle issue (really only happened in the woods...seemed mostly after climbing up hill for awhile...??) it been running good.

Slick761

Some renix problems are very elusive. I believe the French built an early prototype artificially intelligence when they designed this system cause it sure has a mind of its own!! For me, sometimes I get tired of chasing the little gremlins inherent to this 21+ year old system (obvious why they act up, just hit legal drinkin age) and just live with it. If I were a betting man, however, I would refresh your grounds and test and adjust/replace your throttle position sensor

RTorrez1

Just to let you know. Your mechanical fan will always turn when your engine is running. Now that you fixed you elect. fan just keep a close eye on your temp. Like everyone else said there has to be a reason that the po put the bypass in.

Zack92MJ

I don't know if anyones said anything, but if you ac is on the acc fan will be on and running..

Slick761

I finally put a subwoofer in my jeep. The engines and fan dance with the beat. I found techno is the preffered music of my jeep. Haha