GMC Ryan

It was 32 or 33 when I started. I'm located in British Columbia, but have family in Wisconsin. I was last in GB and visited Lambeau in the 2019 off-season.

Update from me.... truck hasn't moved in 24 hours. it was 36F this afternoon and I knew I had to go out this evening, so I plugged the truck in to see what would happen. Truck plugged in three hours, coolant temp is 73F on startup. No engine fans!! Truck built January 2020, latest ECM calibration installed late May 2020 when I purchased. No idea if GM has actually made a fix for the engine fans in the software or if it's just coincidence, but I'm happy. ?

Interesting. Seems rather short-sighted to eliminate the thermostat when GM knows there will be problems plugging in above 0F/-18C. I wonder if you could just get a block heater cord with the thermostat and let that take the guess work out?

I didn't mean to mislead anyone. The Techlink article itself said "available shortly" back in 2019. We're now 14 months past that article and most people would agree that is well beyond "available shortly". This is my sixth GM vehicle with a thermostat in the block heater cord and none of them had an issue with fans coming on when plugged in at too warm of a temperature. If the software engineers can't fix that in 14 months, maybe they should hire new ones.

"If this condition is found, clear the DTC and return the vehicle to the customer. Do not perform any further diagnosis or replace any related components. An updated calibration will be available shortly." That was December 2019.

I'm curious to hear what you find out. My truck was built in January 2020 and not sure if I have the latest ECM programming the Techlink article mentions. Thanks for digging!

I have a Sierra AT4 with the 3.0L Duramax and it is also stamped 9.76 on the rear diff.