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View Full Version : HELP A/C Fan Not working correctly HELP


XJess98
July 14th, 2010, 20:14
I've been researching and reading threads and can't seem to find the same issue I'm having. Keep the advice super simple as I'm not the most mechanical person in the world, but usually can figure things out.

I'll start my Jeep (1998 4.0) with cool engine and things seem fine. If I turn the ac on the electrical fan will turn on but it cycles? It spins fast then slows down as if shutting off. This will continue for maybe 2 minutes then it will completely stop running, any thoughts?

If the engine is at normal operating temperature then the fan does not even turn on even if I turn the a/c on?

Thanks in advance for the help,
XJess98

time2getdirty
July 14th, 2010, 20:43
It is normal for the electrical fan to cycle on and off when the ac is on. I don't understand your last statement; are you sure it is not cycling at normal operating temperature with the ac on?

Jeff-97XJ
July 14th, 2010, 20:50
I've been researching and reading threads and can't seem to find the same issue I'm having. Keep the advice super simple as I'm not the most mechanical person in the world, but usually can figure things out.

I'll start my Jeep (1998 4.0) with cool engine and things seem fine. If I turn the ac on the electrical fan will turn on but it cycles? It spins fast then slows down as if shutting off. This will continue for maybe 2 minutes then it will completely stop running, any thoughts?

If the engine is at normal operating temperature then the fan does not even turn on even if I turn the a/c on?

Thanks in advance for the help,
XJess98

I believe that you are having problems with your #4 solenoid. Very easy and cheap to fix and very easy to check.

I believe your solenoid, for some reason, stops working correctly as soon as it starts heating up. Just my best guess.

Do an advanced search for user 90Pioneer he posted a message a week ago and in his answers is a diagram of the fuse block under your hood, I answered to his thread too, but have no other way to reference it specifically. There are 3 solenoids there with the same number , so you can switch the #4 with another one and see if that helps. If it does, then 14.99 at an auto parts store buys you a new solenoid, and your problem is solved. The solenoid pulls straight out pretty easily.

Let me know how this works for you.

Jeff-97XJ

XJess98
July 14th, 2010, 20:56
time2getdirty - thanks for the response, how I know its not working is one I can't hear it, and two when I was climbing a hill and it got hot I turned the ac on which should have caused the fan to turn on and it did not. I crawled under the jeep and could see that the fan was not turning.

XJess98
July 14th, 2010, 20:57
jeff-97XJ -Thanks I'll try to find the post and check the solenoid I'll let you know what I find. Thanks again.

XJess98
July 14th, 2010, 21:40
jeff-97XJ If its the 90Pioneer post with the picture of the fuses then I found the right post. I replaced #4 today as I had the same suspicion but its still does the same thing. Works at start up but then gets to normal operating temp and fan will not turn on? Also replaced the coolant temperature sensor.

XJess98
July 14th, 2010, 21:45
Also whenyou refer to the "solenoid" I'm guessing this is the same thing as the "relay"? Small black box with 5 conections that plug in.

joe_peters
July 15th, 2010, 00:43
Just jumper power directly to the fan with the engine off and see what it does.

Sounds to me like your fan is dying.

XJess98
July 15th, 2010, 06:41
Thanks joe_peters, I'll give this a try, what should I be looking for? The fan to run and then stop running? I'll let you know what happens. I probably won't get to it today as I'll be working till about 10 pm tonight but check back as I'll post what I find and observe.

kastein
July 15th, 2010, 10:27
Also whenyou refer to the "solenoid" I'm guessing this is the same thing as the "relay"? Small black box with 5 conections that plug in.Not the same thing, but that is what he means. He's using the wrong term, that's all.

I agree with Joe here, sounds to me like the fan is on its last legs. With the vehicle stopped/turned off (don't want to lose fingers in the belt or if the fan decides to turn on), try spinning the blades, do they spin freely (good) or is there a significant amount of drag?

thebrick
July 15th, 2010, 12:55
I've posted this several times before, but a good way to test the electric fan, wiring, relays and PCM...on 97 an up XJs.

While the engine is idling...disconnect the temp sensor on the thermostat housing. After about a second or two after disconnecting...your electric fan should come on and your PCM should throw a code (check engine light).

And it should continue to run (the fan) as long as the engine is running and the temp sensor is unpluged (fail safe mode).

While the engine is running, if you plug the temp sensor back, the fan should turn off after about 2-3 seconds...assuming that you don't have the AC on or your engine temp is not greater then 215-220 F.

And for the AC system...there is this...

http://www.askamechanic.info/askamec...nt/view/73/47/

joe_peters
July 15th, 2010, 14:19
Thanks joe_peters, I'll give this a try, what should I be looking for? The fan to run and then stop running? I'll let you know what happens. I probably won't get to it today as I'll be working till about 10 pm tonight but check back as I'll post what I find and observe.

Your looking for the fan to just run, nice and fast. If it doesn't, if it pulls the same routine of running for a short time and stopping, then you will know for sure that the fan is at fault.

Royal_Highness
July 15th, 2010, 20:35
My fan turns on and off when my A/C is blowing.

The lead tech at my shop told me something along these lines a while ago can't remember what he said exactly...

It only turns on the fan when the high side pressure on the A/C reaches a certain point, and the coolant temperature reaches also a certain point it turns on.

We tested the relays, all tested good. check your relays.

If your fan does not work at all, after it heats up, then maybe the fan motor is going out on you.

If all fails replace with a better one, something that you can turn on and off at will. also runs by itself or something that would be convenient

XJess98
July 15th, 2010, 22:00
All thanks for the advice, sorry it was a long day, got to work at 7 am and just getting home 10:55 pm. Tomorrw I'll check these things that have been suggested and let you know what I find.

XJess98
July 16th, 2010, 22:07
So I think we have determined that the fan is bad. There was power to the fan but it was barley turning and then would stop as it got warm.

What are your recommendations for a replacement?

Does anyone one know what the oe specs are for the original fan?

CFM?

Would you recommend, a total fan replacement or just replace the motor?

Any part numbers would help?

I've seen a couple but only at like autozone or checker, is there something better?

Is there a fan from another vehicle that bolts in?

Thanks again for all your help!!!!!

tuxxj
July 16th, 2010, 22:26
I got my replacement fan for my 97 at the Napa Autoparts warehouse in SLC on 13th S(?). Check their website for your modle and year. You can check the price and who has it near you. You can order it tonight and pick it up in the morning. About $70 IIRC

joe_peters
July 16th, 2010, 22:31
rockauto.com has the fan, various manufacturers, $72-$113.

I would try and pick up one from a salvage yard off of a late model.

tuxxj
July 16th, 2010, 22:36
also be aware that the power plug is different for later years, 97+, I think.

XJess98
July 18th, 2010, 06:43
Thanks everyone for the help the electric motor was definetly bad rplaced it and things work as they should. Tried to find a oe at the junk yard but around here all they had was 96 and older, so I just bought a replacement motor instead of the everything. Took it for a long climb and all worked well.

joe_peters
July 18th, 2010, 16:58
Glad you got it done.

Good luck.

97stomper
September 30th, 2010, 05:34
I have a similar problem with my electric fan in my 97 not coming on at approx 218 deg and above. It has come on with the A/C turned on (however, I didn't run it long and don't remember the engine temp at the time). Last night I hooked my scanner up to the jeep and watched the live data until the temp reached 226...no fan. The gauge is accurate at 210..but doesn't even make it to the next line up for 226, which I find confusing based on the markings and the differential between 210 and the top 260...but that's another topic.

The fan came on and continued to run when I pulled the temp sensor connector, but I didn't have the jeep up to full operating temp at that time either.

Tonight I will try and check the temp sensor disconnect when the engine is hot. Could my fan problem be heat related?

I wouldn't think it is the PCM if it comes on for the A/C and when the ECT sensor is unplugged.

Thanks for your help,

Rob

kastein
September 30th, 2010, 07:13
Yeah, if it comes on when you unplug the CTS/ECT sensor, you can rule out anything except the sensor itself and the temperature of the coolant. Doing that proves that the sensor wiring, ECU, relay wiring, relay, fan, and fuses are all functional.