86SVOwner

2012 SE, 4 cyl, Manual controls, 95,000 miles. Turn on the ac, starts out real cold then after about a minute it goes to full heat. Will not go back to cold unless the engine is shut off then back on. Fuses are all good. Relays for backup lights and compressor are same so I swapped them, no change. I had a similar problem with a Toyota and it was a relay. Found on this thread someone was able to keep the air working by having the headlights on. Figured that was an easy test. Started the car, turned on the headlights, turned on the ac and went for a long ride. All was nice and cool until I turned the headlights off. Within I minute it starts blowing hot air. Pulled over, repeated the process and got the same result. This began yesterday when my wife was driving home from her client’s office. I told her to try the headlight trick when she headed out for the day today. She said it worked like a champ. While searching other similar threads a couple guys commented that theirs blew cold early morning and at night but not during the day. I’m guessing they had their headlights on when it was working. Obviously some type of electrical/electronics issue. Don’t want to spend lots of $$$ for diagnostics and trial and error if someone here has a solution or reasonable suggestions. I’m new to this forum and I appreciate your help.

I have the same issue where having the headlights on allows the air to continue to run cold. Must be an electrical issue...voltage, resistor?!? Any ideas?