electric cooling fan not working

[mikebean]

1066677

Hi, This is a great board. Super information. We have two Cherokees. I drive a 94 Cherokee. My daughters is an 88 Cherokee (her 1st car). She wouldn't drive anything else. While adding refrigerant to the a/c system, I noticed antifreeze/water mixture starting to leak past the hose clamps on the coolant recovery tank. (88 Cherokee, 4.0. auto transmission) I noticed the electric fan, next to the mechanical fan for the radiator, was not blowing. I turned the motor off, she didn't blow. So the motor is overheating. I removed the electric fan and hooked up the wiring to my 94 Cherokee. The fan works OK. I replaced the " coolant fan switch ", I think this is the coolant temp sensor. Still no working fan. This Cherokee has all idiot lights, no gauges. I've had it about a year. No overheating problems until now. Is there a fuse or relay I could check. What have I overlooked? Thanks in advance.[addsig]

 

[Bullet3600]

1066684

On my 88' I wired my fan to a switch on the dash so I can use it only when needed.[addsig]

 

[MudderChuck]

1066689

I´ll apologize in advance, I´ve looked in many XJ´s over the years and have found many different wiring schemes. The thermo switch for the fan is usually a silver dollar sized affair down low on the left hand side of the radiator (as sitting in the drivers seat). Closes at 190-200 F. the relay is usually located just under the hood ledge on the drivers side above the wheel well. The red wire is the power and has a fusable link up stream (fuse built into the wire) number 1 pin on the relay. The number four pin has a red/white wire that goes to the fan and somewhere between the relay and the fan there is a splice and the wire color changes, to red with a yellow stripe I think.
The thermo switch opens and closes the relay, along with the air conditioning controls. There is a diode module wired in between the air conditioning controls and the thermo switch and the relay.
On some models, there is a relay in the same area for the fog lights. If I remeber correctly the fan relay has a red wire, red with white stripe, orange with stripe and black wire.
Jump the thermo switch plugs (up higher by the radiator left near the air box front), and see if the relay actuates and the fan comes on. If not try switching the relay with another for a test and see if the fan comes on with the thermo switch jumped. Check for power (constant) at the 1 pin at the relay. Check the plugs at the diode control module.
The only way I´ve found to succesfully test the thrmo switch is the throw it in a pot of boiling water, fish it out with a pair of tonges and test it quick for continuity before it cools down. I guess a small flame might also work, but also might damage something. If you have to remove the thermal switch, be creful of radiatior damage, a bigger wrench might deform the radiator some.[addsig]

 

[dingus]

1066707

whoah whoah whoah... you have a mechanical fan hooked up to the belt with a fan clutch on the passenger side, and an electric fan hooked up on the drivers side right? the electric fan comes on when the air conditioning is on... i don't think it should come on any other time! (unless you wire it with a switch like others have done)

-nate[addsig]

 

[Bounty__Hunter]

1066724

The aux. fan only came on with the AC on our '98. Your XJ shouldn't be overheating simply due to the aux. fan not coming on, there is another problem.[addsig]

 

[mikebean]

1066726

I found and replaced the relay for the electric fan. When I turn on the a/c the fan comes on now. I have not let it run long enough to come up to operating temperature yet, to see what happens when the a/c is off. Yesterday when I replaced the "coolant fan switch" the coolant looked pretty good, that is, fairly clean. I replaced the coolant with fresh 50/50 mix. [addsig]

 

[Bounty__Hunter]

1066728

Sounds like it's working properly now, have to see if it overheats under normal use.[addsig]

 

[mikebean]

1066730

Thanks all for the great info. This is a great board!!![addsig]

 

[MudderChuck]

1066764

Most every, closed system (cooling system without the radiator cap) there is a switch (like an inch around) screwed into the radiator down low on the drivers side. It is supposed to turn the aux. fan on, when the return coolant to the water pump, goes above 190 F. a little extra cooling when sitting in a traffic jam or such. The aux fan is also tied in with the air conditioning. On the early models, I´ve looked at, there is a connector (two wire) with round pins, up near the air box. On every XJ I´ve had, I´ve re-routed the plug a little, to make it easier to get too, and tied a jumper wire around thetwo wires going to the thermostatic switch (coolant fan switch)(probably different name for the same item). I´ve also made a jumper (short wire with two male spade connecotrs) for the number one pin and the number four pin at the relay (be careful what you jump, one wire is a ground wire black and the red wire has a fuseable link), tied it around the wires close to the relay. Like bullet said, a switch is probably not a bad idea, when doing a lot of slow speed driving in the summer or when trial driving, it wouldn´t be a bad idea to turn the fan on before things get toasty.
On the later models, with the open system, there is probably also a thermostatic switch. But to tell you the truth, I havn´t looked.
Having said all this. between Canadian built Jeeps, those built for export (and sold in the US) and changes in the middle of a model run. The only thing normal about many Jeeps, is they are not normal. I´ve seen several different wiring schemes in the same year Jeep, depending on extras, upgrades and the availability of production parts.[addsig]

 

[MudderChuck]

1066765

Before I forget, most every time I´ve opened the closed cooling system (thermostat replacement etc.)(early model 4 ltr.) I´ve gotten air blocks (bubbles) in there, that mess with the cooling. Squeezing the top radiator hose, helps move the air around. I´ve also seen posts, about parking on a steep hill, nose high, and reving the engine some to get the air moving. The bracket holding the radfiator hose to the air conditioner and/or near/over the battery seems to be where most of the air settles. I installed a flushing connector (garden hose type) with a cap at the highest point on the heater/coolant bottle hose, coming from the thermostat housing, that seems to work well for letting the air out.[addsig]

 

[dibabeedi]

1066834

not sure if it is a fan problem but here goes..............i have a 99 jeep grand cherokee with a v8 and 42k miles on it. i got the "check engine" but when i refilled the tank with gas, it clicked off so i just thought it was maybe a bad tankful. then, about a week later, i noticed that the engine light had come back on again and it was also overheating quite quickly in stop and go traffic and while idling?

does anyone else have this problem and if so, can you give me an idea of what im up against?

oh, and another thing, there is a smell that has appeared almost at the same time as this problem - the thing is is that it smells exactly like the burnoff smoke when you get your fuel injection serviced?know what i mean?

i cant help but think maybe the two are related

edited by: dibabeedi, May 05, 2003 - 04:02 PM[addsig]

 

[dingus]

1066927

dibabeedi - do a self diagnostics on your jeep and it will tell you what is wrong.
[addsig]

 

[Benskate1]

1067085

does your mechinical fan have a clutch? check that, case aux cooling fans shouldnt cause overheating, put in a flex fan($20 at local parts store) with a spacer, i havent overheated since and that includes goin up the mountain trail at a steep incline for a few miles on a fire road where speeds rarely reach over 8mph.[addsig]

 

[dingus]

1067129

benskate - did that flex fan just mount right to the mechanical fan clutch?[addsig]

 

[dibabeedi]

1067244

dibabeedi - do a self diagnostics on your jeep and it will tell you what is wrong.

thanks so much for the help!!!! I am so happy to finally come across a Jeep chat room where folks help each other out ( and it is oddly reassuring that some problems do seem to be common ones, makes me feel less like an idiot.


thanks again everyone!


diana[addsig]