Early 2015 Yukon that I've had since day one. The A/C blows ice cold, then if you adjust it warmer, it blows hot, and I mean hot! Rear A/C seems to cool alright.
Here's the kicker: dealer diagnosed the problem to a leaking evaporator core with an estimated cost of $3,700.
I can understand this if there was absolutely no a/c, but I have trouble understanding why this would be the case given the ability to cool sometimes.
I was thinking blend door actuator, but wouldn't that limit the problem to just one side?