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2000 jeep i6 rad fan not turning on.

4K views 17 replies 6 participants last post by  2005JGC 
#1 ·
This has been an ongoing issue for me esepcially now that it has gotten hotter outside. I replaced the radiator, waterpump,coolant temp sensor and the fan relay. Not only does the fan not turn on when the engine starts to overheat but it would sometimes come on at random. It doesnt turn on when the a/c is activated either.

So i decided to test the fan by hooking it up straight to a battery pack and it worked just fine. The only thing i can think of is that the fan relay that i purslchased from autozone is defective or the coolant temp sensor is not working correctly.

Any input would be fantastic thanks!

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#2 ·
Eventhough the fan works when connected directly to the battery, it still can be that it draws too much current and fries the new relay in a short time. I heard, i think from 2005JGC, that he always changes the fan motor together with the fan relay.
 
#3 ·
So its possible that the relay is fried and would need to replaced along with a new fan. I just turned the jeep on now with the a/c on and the fan kicked on. Like a mind of its own.:slapfight:
 
#4 ·
That is strange indeed. Also have a look now to see if the fan will kick on when the temperature gets too high. What was the max temperature reached before?
 
#5 · (Edited)
It will just keep going up the most it went up to is 250 260 but ofcourse when i drive the air pushes through cooling the engine also on the highway its fine but if i get caught in traffic is the problem. And there have been times when it stayed at 230 i get home check in the engine bay and see the fan running but at the slowest speed ever. Me blowing on it would have made it cool faster
 
#6 ·
Do you have air in your cooling system? HG failure, cracked head, external coolant leak?

I do always check the fan for amperage draw, if it draws too much amperage I do suggest replacement (I have a pretty crude go-no-go test using my power probe that I use). I do feel that a fan drawing too much amperage through the relay will burn it up.

Its tough because with a scan tool you can actuate the fan and verify what is functioning and what is not without worrying about a time limit before you need to get it shut off. Ultimately if you could see your temperature information that your pcm is interpreting...

Your going to need to verify your inputs and outputs to deturmine the problem. Verify the pcm is getting a good signal and that the control side of the circuit works, you can verify your output side (including through the relay) by grounding the pcm control on the relay, (iirc the 3rd pin from the left with the latch on the top looking into the connector, the second to the left should be your + to run the fan, pins 1 and 4 are power and ground respectively) Right now my access to diagrams is down (site maintainence?) If I have some time tomorrow Ill add some suggestions.
 
#7 ·
Not sure its air in the cooling system i'm not losing any coolant thats for sure. Its come down to it i'm going to replace fan first then see what happens from there because its the only thing i did not replace... if the relay is burnt out I can bring it back to autozone for replacement. after that i appreciate this help i figure in the back of my mind that it might be something electrical.
 
#8 ·
Little update today... When I got to work this morning and popped open the hood to see the fan not functioning again, did didn't really start to overheat but you culd tell it was about to. So i decided to spin the fan a little bit and the fan kicks on but at very low speed. At this point im thinking the relay is not functioning correctly or the fan is blown to @#$%. Maybe when i get home ill have to time to check everything out.
 
#9 ·
This looks more as a fan motor problem. A relay normally works fine, or not at all.
By the way, take care spinning the fan by hand with the engine hot. It could suddenly start running and eventually hit a finger.
 
#14 ·
Took out the fan the other night cleaned it up took it apart with a can of air and wd40 tested it on a 12v batter and worked just fine after cleaning it up. The connector clips i also took a look at and they looked REALLY oxidized to the point where i couldn't clean them without messing something up. As a temp fix i cut both fan and power wire and tied them together without the connectors. Happy to say this worked fantastically and everything works perfect! :thumbsup:
 
#16 ·
HAD THIS SAME EXACT PROBLEM...

Couple of things:
1.) replace the fan motor & the relay at the same time. IME, when the relay is fried so is the motor. The problem probably started at the motor & took out the relay. At least that is what happened in my case.

2.) Use only a Mopar relay. It will cost a little more, but worth the aggravation. I used 3 different relays that worked for about 2 months each & then would go out. since the issue was with the crappy relay, it didn't affect the fan motor.

3.) Handle this sooner than later. If left un-repaired for too long, this will start causing error codes to generate for different areas of the jeep. i.e. tranny codes, evaporation leak codes, etc. I found that as soon as I fixed this issue, all other codes ceased popping up...

4.) DO NOT use the shortcut method to replacing the relay. It did not take ll that much time to remove the front grill & headlight to access the relay location.


hope this helps...
 
#18 ·
HAD THIS SAME EXACT PROBLEM...

4.) DO NOT use the shortcut method to replacing the relay. It did not take ll that much time to remove the front grill & headlight to access the relay location.

Whats wrong with the shortcut method? Consider your on a trip 100 miles from home/ out 30mi from the nearest paved road on forest service roads hunting/ out wheeling on OHV trails... you name it, and you start overheating, what is going to be easier, to remove the facia and support or to remove the 1 7mm headlamp bolt and pop the housing out and replace the relay?

Its a common enough of a failure and still in a VERY safe spot with the added opening.
 
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