Cooling fans come on as soon as I turn on the engine; AC won't get cold

[agjackson1981]

I have a 2017 Yukon Denali. The cooling fans come on as soon as I turn the engine on. I've been trying to find out the problem, but can't get a clear answer. I replaced the thermostat and the cooling temperature sensor. It still didn't fix the problem. I've checked it with the AC being on and off, and the fans still run on high. The AC blows fine, but it decides when it wants to be cool or not. I don't know what else to do. Does anyone know what's happening?

 

[Geotrash]

I have a 2017 Yukon Denali. The cooling fans come on as soon as I turn the engine on. I've been trying to find out the problem, but can't get a clear answer. I replaced the thermostat and the cooling temperature sensor. It still didn't fix the problem. I've checked it with the AC being on and off, and the fans still run on high. The AC blows fine, but it decides when it wants to be cool or not. I don't know what else to do. Does anyone know what's happening?

Did you replace the coolant temp sensor with an OEM ACDelco part from a known good supplier (not Amazon)? Did you also replace the pigtail on the sensor? We’ve seen lots of instances of aftermarket sensors not working and broken wires near the sensor.

Finally, do you have access to a code reader that can read all modules? You’d need something that can show commanded fan speed vs actual.

 

[jaxscuby]

how about this..did you clear the code?