Auxiliary fan not running

bustednutz · Jun 10, 2005

With the weather getting downright hot here, I noticed that my aux fan is not running.
I took a jumper wire directly to the battery and it ran. So the fan does work.
I checked the fuse in the main panel #25 or 24 15A, and thats good.
I also checked the fuse in the main powerblock under the hood. Its also good.
So all thats left is the relay I guess.
It does not come on at all with the AC nor when the engine temp gets hot at idle.
Any other ideas where to check?

JJacobs · Jun 11, 2005

Relay, temp sender in radiator, wiring.

bustednutz · Jun 11, 2005

Found the problem. The CTS plug needed to be unpluged and pluged in again. Must have had a loose connection or some corrosion.
Keeping an eye on it.

graVes14 · Jun 12, 2005

what and where is the cts plug b/c im having the same problem...

Dr. Dyno · Jun 12, 2005

The CTS is in the t'stat housing on '91+ XJ's and has a connector with two wires attached to it.

graVes14 · Jun 18, 2005

i was thinking about putting the aux fan on a manual switch so i could turn it on when wheeling or towing. I mean it didint turn on when i overheated in the mud last week adn my engine was at 270 so it couldnt hurt right? anyone else done this?

cykaaro · Jun 18, 2005

THought mine was not working at all, but finally had it kick in the other week when I was screwing around in mud at a construction site. Good to know it works. For whatever reason, my engine seems to run pretty cool I've found. Still though, thinking of putting a manual switch option in for when I think I need the extra cooling.......Just haven't researched yet how to actually wire it in.

graVes14 · Jun 19, 2005

one way to hack it is just to run a seprate power wire spliced into the + wire of the fan then run that through a switch. so you hit the switch..instant power, the engine decides to make it run ( mine never has) it still can run. I dont know how much amperage the fan pulls, you might need a relay or somethign but...

5-90 · Jun 19, 2005

Makes enough sense to me - I do it to my XJs as a standard mod. For the RENIX (87-90,) you just wire a toggle switch in parallel with the thermal switch in the driver's side radiator tank and call it a day.

For the later models, find the fan relay, figure out whether it needs a "ground trip" or "hot trip" (all my XJ's are RENIX) and simulate the signal with a toggle switch.

The current draw of the fan is significant - it should not be wired direclty to a panel switch. Trip the relay, and you have a safer mod - and your switches will last longer.

5-90

graVes14 said:
i was thinking about putting the aux fan on a manual switch so i could turn it on when wheeling or towing. I mean it didint turn on when i overheated in the mud last week adn my engine was at 270 so it couldnt hurt right? anyone else done this?

drifto77 · Jun 19, 2005

So can someone tell me .. what is it that tells the relay to turn the aux fan on, I know about the sender in the t-stat houseing, but were does it go from there?
My aux fan WONT come on unless I turn the air cond or the defrost on. I have replaced both the temp-sender in the back of the head and the coolant tep sensor in the t-stast houseing. The relay is good and I dont want to run it thru a switch if I dont have to (i would forget it). Also I saw the mod to run it thru a GM(?) adj contronl some where, guess I need to see if I can find that agian and take another look at it. (iam really NO GOOD at doing things like that)

BTW..... Its a ' 91.

Wayne Sihler · Jun 19, 2005

drifto77 said:
So can someone tell me .. what is it that tells the relay to turn the aux fan on, I know about the sender in the t-stat houseing, but were does it go from there?
My aux fan WONT come on unless I turn the air cond or the defrost on. I have replaced both the temp-sender in the back of the head and the coolant tep sensor in the t-stast houseing. The relay is good and I dont want to run it thru a switch if I dont have to (i would forget it). Also I saw the mod to run it thru a GM(?) adj contronl some where, guess I need to see if I can find that agian and take another look at it. (iam really NO GOOD at doing things like that)

BTW..... Its a ' 91.

The sensor in the T-stat housing,which runs into the engine controler turns the fan on at about 215-220*.
I put a Tee fitting in and a sensor(GM style-1 wire) to a relay and thru a switch(manual overide) and then to the fan.Switch is to relay. Turbo City used to make a fan relay but don,t anymore.
Check go jeeps web site for his write up.
Wayne

drifto77 · Jun 21, 2005

Wayne Sihler said:
The sensor in the T-stat housing,which runs into the engine controler turns the fan on at about 215-220*.

New sensor..... still dont come on. Is the engine controler part of the computer or what? (iam lost when it comes to all this computer stuff they put on cars/trucks these days

)

Wayne Sihler said:
Check go jeeps web site for his write up.
Wayne

I'll check it out.

Wayne Sihler · Jun 22, 2005

drifto77 said:
New sensor..... still dont come on. Is the engine controler part of the computer or what? (iam lost when it comes to all this computer stuff they put on cars/trucks these days )

Yes it is the computer,controler or as the engineer called it "JTEC"
As the sensor is in the thermostat housing it sees mostly the water at the thermostat.The guage sees the temp at the back of the head.
Wayne

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Auxiliary fan not running

bustednutz

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JJacobs

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bustednutz

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graVes14

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Dr. Dyno

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graVes14

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cykaaro

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graVes14

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5-90

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drifto77

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Wayne Sihler

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drifto77

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Wayne Sihler

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