# Engine fan stuck on constantly, even with all relays removed..



## RickFerguson (Feb 10, 2017)

Have a 2014 Cruze deisel. Bought it with MIL on and engine fan not working.

Mil is p0691.

I tested the power and ground going to the fan, found it was good. Fan felt a little iffy to me. Just finished replacing fan. Install everything, hook up battery and the fan is running constant, key off.

Checked wiring diagrams and according to mitchells the fan has power and ground at all times and there is a control speed wire.

I removed all 5 relays related to the fan, even tried the ignition relays, all removed with key off and fan still runs, only way to get fan off is removing 60a fuse.

I checked the control wire at PCM for shorts to power and ground , both ok, and wire has perfect resistance. I even tried removing connector 1 from PCM, fan still runs....

Pulling out my hair, any ideas ? and coolant level is good.

Using scanner the only thing i see out of place is ambient air sensor is reading -14°c all the time, even with it unplugged. The connector looks good though, and ECT is reading properly.


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## ChevyGuy (Dec 13, 2014)

Assuming the cooling fan system is like the gasser, I'd say either you've failed to pull the high speed relay, or you have a short in the fuseblock. Note that the fuseblock is easily removable. Pull the bolts and I think it just unplugs from the bottom.


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## RickFerguson (Feb 10, 2017)

All relays were removed, triple checked just now, tried one at a time and all of them out, fan still on.
Had the fuse panel out to check corrosion or bad connections, all appeared ok and saw nothing out of place. Looked under the box for wires rubbing or anything, all ok


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## ChevyGuy (Dec 13, 2014)

RickFerguson said:


> Checked wiring diagrams and according to mitchells the fan has power and ground at all times and there is a control speed wire.


If you're looking at the output of the BCM, that would be true. But at least for the gasser, that would not be true of the fan itself. (And yes, the gasser has 5 relays for controlling the fan.)

Hmmmm. Are you sure you put in the right fan? If the diesel is really a different animal and the speed control is part of the fan, that could be a problem. For the gasser, if the fan gets power, it's going to run. Period. Those 5 relays control which of the 3 power lines to the fan gets power to select the fan speed. With the relays removed, unless there's a short or your car's name is "Christine", there's no way for power to get to the fan.

Since you bought the car in this condition, don't overlook the possibility that you're dealing with a hack job of putting a common Cruze fan into a rare diesel. They are different part numbers. But I don't have diagrams for the diesel system so I'm not sure how much the control systems have in common.


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## RickFerguson (Feb 10, 2017)

I just installed new fan myself, because the original was burnt out.
I put in a Four Seasons fan part number 76243 . Just double checked there site and thats listed for the deisel


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## RickFerguson (Feb 10, 2017)

So..... i just looked up on their site and they have the same one listed for gas and deisels..... damnit

Maybe thats issue ??


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## EricSmit (Dec 21, 2016)

You went from a fan that does nothing to a fan that does everything. Talk about a try hard. hahahaha. 

Have you asked your local dealership's parts department?


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## ChevyGuy (Dec 13, 2014)

RickFerguson said:


> So..... i just looked up on their site and they have the same one listed for gas and deisels..... damnit
> 
> Maybe thats issue ??


That could be it. I tend to go to GMPartsExpress.com to look up parts. I got different GM numbers. Different drawings as well.

Interestingly, there's a different part number for manual transmission Cruzes. Not sure why that would be. Maybe different flow rates?

I'd suggest going back to the manual and comparing the wiring for the gasser and the diesel. If they're the same, then maybe this will work. If they're different - then that's probably the problem.


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## diesel (Jun 8, 2013)

This is the first I've heard of a fan issue in over 3 years on this forum. Was the car in a wreck prior to your purchase?


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## Snipesy (Dec 7, 2015)

I had the O2 sensor pop out of mine and chew up the fan after i bought it. I made them replace both the O2 sensor and the fan. Was around $900 in parts but it was on GM's dime.

It works just like it always has.


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## diesel (Jun 8, 2013)

Snipesy said:


> I had the O2 sensor pop out of mine and chew up the fan after i bought it. I made them replace both the O2 sensor and the fan. Was around $900 in parts but it was on GM's dime.
> 
> It works just like it always has.


That's interesting! If you posted about it before, I don't remember.


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## wow (May 20, 2017)

Rickferguson, did you get to find the solution to your problem?


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## gndpooba (May 21, 2020)

The solution is that the DIESEL Cruze and the GAS Cruze take different cooling fans. If you used Four Seasons, or several other cross references, you will end up with the wrong part. GAS fans and DIESEL fans look almost identical. Several long hours later, when you put the battery cable back on, the fan will run at high speed even when the engine is off. Pulling the 5 cooling fan relays will have no effect, the fan will still run. The only way to turn it off is pull the 60A Cooling fan fuse. If you look closely at the fan you removed, the connector on the DIESEL fan is wired to a 2" x 3" solid state box where the GAS fan is connected to a group of resistors. The fix is to order the OEM DIESEL fan, which comes as a fan motor, fan blade, and the Pulse Width Modulator (the little black box between the connector and the fan motor). The GAS Cruze fan usually comes with the Shroud. If you ordered one with a shroud attached, you likely ordered the wrong part. If you've gotten this far and want to confirm your original is bad, check for 12v between the two large terminals on the fan shroud connector. if you have 12V, most likely the PWM has failed. The fan motors don't normally go bad and the only way to get the PWM is with the fan.


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