# Cooling fan issue



## burgett2103 (Sep 28, 2019)

Hello all. I am new to this site. I have searched and searched and cannot find a cure for my car.

I have a 15 LT 1.4. My engine cooling fan will only run on high. So far I have replaced the entire cooling fan assembly along with the thermostat just an hour ago and it still has the same problem. 3 days ago when I switched fans, it cured my car for 2 days and today it started up again so I went with my second option and replaced thermostat assembly. 

I just tried a new relay switch on micro relay 12 in fuse box and that didnt fix it either. I am clueless at this point. 

What are the odds of a faulty fan? I'm about to switch back to my stock fan and return the other to auto Zone. 

Please help with any other possibilities.
Thanks in advance.


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## burgett2103 (Sep 28, 2019)

The fan does not run constantly. About every 20 seconds it will turn on like a jet for about 5 seconds and then shut off, repeat. When I swapped fans, it worked. I had my lower fan speeds and never turned on like a jet. Car has almost 97k on it.


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## Eddy Cruze (Jan 10, 2014)

Did you try the Search feature?









Search results for query: hi fan speed







www.cruzetalk.com


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## burgett2103 (Sep 28, 2019)

Ya. I know how forums work


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## burgett2103 (Sep 28, 2019)

Did you even read my post? Literally the 2nd sentence. I'm hunting for a fix dont have time for a wise a$$ comment.


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## plano-doug (Jul 1, 2015)

burgett2103 said:


> The fan does not run constantly. About every 20 seconds it will turn on like a jet for about 5 seconds and then shut off, repeat. When I swapped fans, it worked. I had my lower fan speeds and never turned on like a jet. Car has almost 97k on it.


So, with the new fan installed, it worked correctly for a few days, then went back to running only on high. At first, I was thinking one of the fan relays might be bad. But if that was the case, replacing the fan should not have made any difference. So that leaves me thinking it could be in the wiring, most likely at the connector to the fan. I would inspect pins 2 and 3 in that connector to make sure they are making good contact.

Since that connector was handled during the fan installation, and the fan worked correctly afterward, I'm thinking that pins 2 and 3 had their connections restored for a while, then worked their way loose again.

I've attached a drawing I have. It's for a 2013, but should be the same.

HTH.

Doug

[Edit]BTW, to test the fan, with the connector open, connect pin 1 to GND, and jumper +12V to pin 2 (med), and then pin 3 (low). This will confirm whether there is any issue with the old fan.
.


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## ChevyGuy (Dec 13, 2014)

Usually the 


burgett2103 said:


> The fan does not run constantly. About every 20 seconds it will turn on like a jet for about 5 seconds and then shut off, repeat. When I swapped fans, it worked.


That's usually a bad fan. More specifically, a fan whose resistor pack has burned out such that only "high" works. It's possible you got a defective part.

But something to check - make sure the A/C isn't coming on. (Not turning it on is not enough, it will turn of if you have floor vents selected for example.) Perhaps unplug the compressor. See if you still have the problem. If not, then it's an A/C problem causing excessive pressure in the system which is interpreted as "too hot".


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## burgett2103 (Sep 28, 2019)

I initially had it inspected at dealership when I had tires put on. They spent a few hours and came back with a bad fan. I havent personally tested the harness itself but I will give that s shot. Thanks for the response!


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## burgett2103 (Sep 28, 2019)

That's what I thought was the bad resistors that's why I replaced the fan. It worked for 2 days! 

I should have specified that i only have jet fan speed when the ac is on, and i never actually hear fan kick on when idling without ac on. 

But what I dont understand is why it worked perfectly normal for 2 days and back to it's old ways.

I do have a new update. So while swapping fans I remove trans cooler lines from the core to make for easy removal so a little bit of oil leaks out while swapping. Yesterday one of those lines shot out of the core and lost all oil, and I was broke down 3 blocks from home. I refilled 4 quarts. Didnt look full. I proceeded to put 12 quarts of fluid in (yes I know I knew something wasnt right) to finally see it all leak out while car moves. I havent been able to dig and find where it's coming from just yet. What I'm wanting to know is if low trans fluid has anything to do with my cooling fan running as I've described?


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## ChevyGuy (Dec 13, 2014)

burgett2103 said:


> What I'm wanting to know is if low trans fluid has anything to do with my cooling fan running as I've described?


Not sure. If you were driving enough to overheat the transmission, I could see that happening. But that's a pretty unusual



burgett2103 said:


> I should have specified that i only have jet fan speed when the ac is on, and i never actually hear fan kick on when idling without ac on.


I'd have the A/C checked. I believe a restricted orifice can cause that. However, unless the car's hot, it probably does't need a fan unless the A/C is running. And at that point, if it can't get low or medium speed, it's going to escalate pretty quick.


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## Blasirl (Mar 31, 2015)

burgett2103 said:


> Hello all. I am new to this site. I have searched and searched and cannot find a cure for my car.





Eddy Cruze said:


> Did you try the Search feature?
> 
> 
> 
> ...





burgett2103 said:


> Did you even read my post? Literally the 2nd sentence. *I'm hunting for a fix dont have time for a wise a$$ comment.*


Well, for the record, he asked a valid question. We get a ton of repeat questions here. Your statement that you searched and searched doesn't give much specifics as to what you searched for or where you searched for it. Even though Eddy can be a bit crotchety, he has his place here like all of us. 

As for having time to do anything on this forum, we are all volunteers including most of the administrators. We do not work for Chevy or Verticalscope. If I did this would be a great gig (even though I still hate the new software). I squeeze all my flippant answers into this forum between a full time job, three school age kids and a very demanding wife (JK), and four broken down vehicles. .


Now having said all of that, did you test your two coolant sensors? If one or both are bad, the fan runs like a jet.

Have you washed the engine bay recently? If so, use some compressed air in the connector and the sensor after unplugging them as water in there will also cause this.


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## Eddy Cruze (Jan 10, 2014)

burgett2103 said:


> Ya. I know how forums work





burgett2103 said:


> Did you even read my post? Literally the 2nd sentence. I'm hunting for a fix dont have time for a wise a$$ comment.


Booger, at least you didn't accuse the entire group of wasting your time. Happy Motoring!
bsdubois said:
"I have come to a conclusion. This group is full of a$$holes. I am sorry I wasted my time on suck a pathetic group. I made the mistake in presuming people have the ability to work on their own vehicles. Obviously, this is not the case.

I am sorry I wasted my time".


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## burgett2103 (Sep 28, 2019)

I apologize myself for being a wise a$$ about your comment, this car is one thing after another cant catch a break. All the things I said I've done I have found on here, and finally made a post about it because I cannot seem to get a fix for it. 

I replaced 1 coolant temp sensor, the one at the bottom left before it goes into the radiator. Where is the 2nd located? 

Just dropped car off at body shop for a new front bumper today, so I wont be able to check more things for a few days.

What do I need to check with a/c system if that's the cause? 

The car itself does not ever get hot enough for a fan to kick on without a/c on. But when I did replace the fan, it worked like it should with a/c turned on, on lower speeds for only 2 days and then back to jet speed only it went. This car is killing me.

Trans problem has been taken care of. It was wayyyyy overfilled. Not sure where all the fluid came out of, but I did find the proper way to check fluid amount and it's now good to go.

Thanks guys, and sorry for being a d!ck, took your comment the wrong way!

I will try blowing connectors out because I have washed it but it was doing this prior to that.


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## Blasirl (Mar 31, 2015)




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## jblackburn (Apr 14, 2012)

Was the AC system refilled at some point? It could be overcharged or have another problem like the expansion valve causing high side pressure to trigger the high fan speed.

Typically it is the fan itself, though...the ECU should only summon high speed if the engine is above 230F (or temp sensors are acting up), or if the AC high-side pressure is very high on a hot day (or high pressures caused because low/medium speed is not kicking on).


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## billy_j844 (Oct 30, 2016)

I had that fan problem a while back. Seems that some d***head overcharged my A/C. Pressures were too high. Removed some refrigerant, no problems since.


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## burgett2103 (Sep 28, 2019)

Ever since I replaced radiator I've had the issue. I just tried the overcharged a/c this weekend and that didnt fix it. However, I replaced radiator because of a small leak and the tabs broke so it was "floating" after I hit the raccoons. I had the bend my condenser and intercooler back to as straight as possible to fit my brand new straight radiator as well as refill my a/c. I've also had like a purging air sound almost since then as well. I'm beginning to wonder if my condenser could be a cause? What is the sensor that goes into the condenser called? Body shop called and asked if I wanted them replaced so I'm getting a new condenser and intercooler too. Thanks for the replies guys.

So how likely is it that I did get a faulty fan the first time around? Never did try a 2nd new one. Just strange it only worked for 2 days like it should.


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## Blasirl (Mar 31, 2015)

Just be wary of the exposed clips!


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## burgett2103 (Sep 28, 2019)

Update. Got car back today. New bumper as well as condenser and intercooler. Still have fan issue.

I have unplugged and cleaned any sensor in relation to fan problem. I started car as a test run after each individual cleaning. The last one I checked was the first coolant temp sensor located right off the engine. Once I plugged back in and started I had no temp read at all on my dash and fan ran on high non stop. Will not shut off. Is this a sign that this sensor is in fact bad?

I waited about 45 minutes and started car again and I did get a temp read on dash but fan also stayed on high without ever shutting off. This is also without my a/c on and HVAC completely off. I'm not sure if this 1 sensor can do all of this, but that's what I really need to know right now.

This is the last thing I'm trying until spring to fix, however, I now need a fix to stop my fan from running nonstop without removing a relay.


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