We have owned multiple GM vehicles with automatic climate control systems, including a 2010 Enclave that we traded for this 2018. We know how these systems are supposed to work. Set your preferred temp and the system cools the cabin until it reaches the desired temp. Once it gets to the desired temp the fan speed is decreased to just a trickle but there is still cool air coming from the vents. The fan speed increases when it needs to cool the cabin again. Pretty simple system that's been around for 15yrs or more. This is how all of our other GM autos work. That said, here is our problem.

Instead of the fan speed decreasing, the air coming from the vents changes. The fan never drops it's speed at all. It actually blows warm humid air which significantly and quickly heats up the cabin. The fan never drops below a medium fan speed. After the first few cycles of this we hear a loud hissing sound from behind the dashboard. This is how our automatic climate control system works. Cool for a bit, heat for a bit, cool, heat, HISS, cool, heat, HISS, repeat. This all the time. It doesn't matter what temp the climate control zones are set at (we've tried 78-68 degrees) or how hot it is outside (82-98 degrees with average 85% humidity).

I took it to the dealer service and was told that it's working as designed. The tech suggested that I not use auto mode and instead use the recirculate option at all times. I tried that with him in the car and it blew hot air at us. He replied that is how it's supposed to work. He said the hissing sound is the expansion valve and that's normal. I took it to a different GM dealership and they could not find a problem even as I showed them what it was doing while in the car with them. I also was give the keys to another 2018 Enclave on the sales lot. It did the same thing as mine does.

This is ridiculous. A $50,000 car should be able to keep a cabin cool without hissing or blowing hot air. All I want is for the A/C in our brand new Enclave to work the same as it did in our 8yr old one. Or my 2015 Yukon and 5 other GM vehicles that we've owned. I called Buick Customer Service and asked if what I'm experiencing is the way the system is supposed to work or not. they are investigating my issue. I just want it fixed. If this is the way it's supposed to work them we are getting rid of this car. At this price point we should not be sweating after 20min in our car with the A/C set on 70 degrees. I am curious to see if anyone else is having this problem. Please let me know!