Ac blows hot, cooling fan never gets to high speed

[Migs1369]

I have a 2015 Silverado with 110k recently I’ve had trouble with my AC not working as it should, sometimes at start up it blows hot air and eventually will blow cold air but it’s not as cold and doesn’t come out as strong as it should. I’ve already hooked up the truck to an AC Machine and did a vacuum and leak test and both are good and refilled Freon back to spec, replaced in-cab air filter, passenger blend door, checked all fuses and relays, did reset on AC system. One thing that is happening is that both radiator fans hesitate to start when AC is turned to high and both fans never blow at high speed, when engine temp sensor is unplugged the fans will spin in high speed but will eventually slow back down to initial speed.

[Jsdirt]

Without more, it's hard to guess, but it does sound like you're not getting proper condenser airflow. Fans need to work as designed, AND the condenser should be clean - especially in between the condenser and radiator. Debris loves to pile up in there.

 

With a set of gauges on it, if your pressures go sky high until you command the fans to high speed, then that's your problem.

 

Could be a number of things on a '15, too, like blend door issues as well. But I would focus on the fans & temp sensors. You can check operation easily with a scan tool. If you want to go deeper in testing, check out ScannerDanner on YouTube.