Air Conditioner problems of the 2017 Chevrolet Colorado

The air conditioner periodically and at random will freeze up on trips over 1/2 hour. I have taken it to the dealer twice. Once they could duplicate the problem and replaced the evaporator temperature sensor. But I still have the problem. This last time they kept the vehicle two days and couldn't duplicate the problem. I have measured the vent air temperature as low as 35 degrees (the temp sensor should not allow this) and have also measured the temp at 40 degrees f at which time it started to freeze up. When this occurs, the volume of airflow drops, the vent air temperature starts to climb and if I stop and open the hood I will see ice on the evaporator line. The problem has occurred on the highway on 2 to 3 hour trips but also has occurred on a 1 hour trip at 50 mph and also a 1/2 hour trip in city (stop and go) traffic. The ac compressor does not appear to ever turn off, unless I push the button to turn off the ac. The dealer cannot fix. Gm engineers are studying but don't have a solution.

When run in high heat, a valve in the air conditioning system freezes up and shuts down the system. The system needs to be turned off until the valve until it defrosts before the system resumes to operate. I took it into the dealership and was told that it is a known problem and that the manufacturer is looking into ways to repair it and would notify me. I was also told that the system in my vehicle is also used in other models and affects them all. It has been 8 over months and nothing has been heard from the dealer. I sent them a message inquiring and they have not responded. I don't know if this qualifies as a safety complaint that your department investigates but not having a working a/c when driving across the desert in 120+ degree heat is not conducive to good health. Thank you for your time.

Air conditioning is intermittent/blows warm/emits fog from vents. The dealer says no fix available yet cites per doc id:5125499. Says engineering is studying problem. Mine stops working-blows warm with in 1/2 hour. Also in stop/go traffic the transmission downshifts abruptly and causes truck to accelerate forward-have to apply brakes hard to avoid collision. Dealer says can not repeat but shifting is consistently abrupt and I have asked about software updates to allieviate this safty concern to no avail.