Cooling fans not running, but no overheating. Normal in cold weather?

[KATfishing]

2008 Yukon Denali, 6.2l, 160K. I don't hear my cooling fans running when I go to shut off the vehicle no matter how far of a trip I'm making. It's been cold in Wisconsin, mainly in the teens and 20s. Vehicle doesn't overheat. Temp gauge is right in the middle where it has always been. Heater blows nice heat. Coolant is in the zone for cold engine when I check it. Is it normal for it not to run if it's cold outside?

 

[swathdiver]

Not sure is my answer. I would turn on the AC and try to get her hot, pop the hood and look/listen for the fans to at least turn on their low speed setting. Fans always run in unison.

Know anyone with a fancy scan tool? You can turn them on for testing with one. Check and test your fuses and relays first if the fans really are not running.

From the shop manual:

The PCM commands the low speed cooling fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 94.5°C (202°F).
 A/C refrigerant pressure exceeds 1447 kPa (210 psi).
 After the vehicle is shut OFF if the engine coolant temperature at key-off is greater than 101°C (214°F) the low speed fans will run for a minimum of 60 seconds After 60 seconds, if the coolant temperature drops below 101°C (214°F) the fans will shut OFF. The fans will automatically shut OFF after 3 min. regardless of coolant temperature.

The PCM commands the high speed fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 104.25°C (220°F).
 A/C refrigerant pressure exceeds approximately 1824 kPa (265 psi).
 When certain DTCs set.

At idle and very low vehicle speeds the cooling fans are only allowed to increase in speed if required. This insures idle stability by preventing the fans from cycling between high and low speed.

 

[OR VietVet]

One last thing to add. In about 90% of the time, you don't need a fan, mechanical or electrical when traveling at highway speeds. If towing then I still say a fan is needed. You may be cold enough there to not need the fans on and also depends on the type of driving you are doing. If is mainly stop and go in town at lower speeds I would think your fans should kick on.

 

[KATfishing]

Not sure is my answer. I would turn on the AC and try to get her hot, pop the hood and look/listen for the fans to at least turn on their low speed setting. Fans always run in unison.

Know anyone with a fancy scan tool? You can turn them on for testing with one. Check and test your fuses and relays first if the fans really are not running.

From the shop manual:

The PCM commands the low speed cooling fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 94.5°C (202°F).
 A/C refrigerant pressure exceeds 1447 kPa (210 psi).
 After the vehicle is shut OFF if the engine coolant temperature at key-off is greater than 101°C (214°F) the low speed fans will run for a minimum of 60 seconds After 60 seconds, if the coolant temperature drops below 101°C (214°F) the fans will shut OFF. The fans will automatically shut OFF after 3 min. regardless of coolant temperature.

The PCM commands the high speed fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 104.25°C (220°F).
 A/C refrigerant pressure exceeds approximately 1824 kPa (265 psi).
 When certain DTCs set.

At idle and very low vehicle speeds the cooling fans are only allowed to increase in speed if required. This insures idle stability by preventing the fans from cycling between high and low speed.

Thank you for the great info! I'll try to kick them on with the A/C when the engine is warmed up. It's helpful to know how the fans work. Merry Christmas, Swath!

 

[KATfishing]

One last thing to add. In about 90% of the time, you don't need a fan, mechanical or electrical when traveling at highway speeds. If towing then I still say a fan is needed. You may be cold enough there to not need the fans on and also depends on the type of driving you are doing. If is mainly stop and go in town at lower speeds I would think your fans should kick on.

Thanks for this additional info... It's very helpful. Merry Christmas!

 

[intheburbs]

Compressor might not kick on if it's too cold, which would leave the fan(s) off.

If you don't have a scan tool, you might have to wait until the temperature is above about 50.

 

[OR VietVet]

Compressor might not kick on if it's too cold, which would leave the fan(s) off.

If you don't have a scan tool, you might have to wait until the temperature is above about 50.

Put it in your heated garage and crank up the heater.

 

[usnret]

Mine aren't kicking in either, but most of my driving is 50MPH or higher. Winter is here in NW Wis.

 

[LRD_V8R]

From my tuning work on my other car, it's completely reasonable for the temps to get under 202 F when you are not regularly stopping, and that's down here in TN. This would rarely happen in the summer, but does happen frequently when it gets cold(er) here.

 

[mikeyss]

I heard mine come on today on low for the first time in awhile. I didn't have the A/C on, but with the tune, they will come on at at lower temp. It was almost 60 today, hard to imagine a few weeks ago we had 18" of snow.