2017 1500 Cooling Fans Always Run

[DeePa]

All,

 

Recently, the cooling fans in my 2017 Sierra 1500 run all the time.  It sounds like a freaking jet.  They never used to act this way.

 

They start when the truck is started and never shut off and appear to be on at least 50 %, if not more.   Its very loud and the truck never warms up 100% if I'm sitting in it while idling with the heat on.  The engine temp gauge actually drops when it's idling and I turn the heat on.  The heat is lukewarm also as the coolant isn't up to temperature.  This truck never used to act like this.

 

I have checked the active grill shutters and they do their self test when the truck is first started...they start open, fully close, and re open.

 

I have tried to reset the ECU by disconnecting the negative battery cable for 20 minutes and turning the lights on to discharge any stored voltage.  The fans did not turn on immediately when restarted, but eventually turned on slow, then increased to full speed and stayed on while the truck was parked and idling, just like before the reset.

 

The truck is still under warranty and will be going to the dealer at some point for a wheel balance/alignment/oil change after my 5100's are installed.  Just checking to see if anyone has run into this issue before.  I have read about disconnecting the MAF while changing a headlight or something and having this happen, but I have not touched anything on this truck.  Also, the coolant level is just under the full cold mark...I'll start monitoring that too as my 2014 has the radiator replaced under warranty because it cracked at the plastic sides of the rad on the passenger side.

Thanks,

 

Mike

 

 

 

[Colossus]

might be a software update to address this. 

[redwngr]

Sounds like a dealer visit is in order. 

 

I'm gonna bet there is either a fault making the fan unable to disengage OR a bad sensor resulting in the ecm commanding the fan to 'on' as a default.

Edited December 22, 2017 by redwngr

[Gibby96]

Do you have an update on what was causing this?

[DeePa]

No. It just stopped a few weeks later and never happened again. 
 

it may have been something with the AC even though it was in the middle of winter. 

[flyingfool]

usually when the t-sat fails to close the engine never warms up, the fans stay on in failsafe mode, if it stopped doing this then the t-stat might have unstuck itself and is working normally again

[txmuder]

Yes mine did this....replaced the engine temp sensor and the problem when away.