I brought my car to the dealer to have my Mountune Quick Shift installed. Nice!! When I drove it home, I noticed the A/C was completely dead and blowing hot air. It was colder outside!. Went back to the dealer: "Your tech knocked out my AC." Anyway, they checked all the connections and the tech did not make any mistake, except it just wasn't working . Made an appointment to have the problem diagnosed. Next morning I thought I was going to drive around in a hot car. I start the car and it worked all of a sudden, A/C was refrigerator cold as if nothing happened. Called the service writer and cancelled the appointment. We fiddled with the switches to now avail. Checked the coolant and it was fine. Should I have used the voice commands to turn it on and off? Does anyone any idea what may have happened?