I don't know if this issue has come up with others, but on my 2012 sonic ls with basic hvac controls, my ac works great..... until I switch it to hot and run the defrost for a bit, and then when switching back to panel and ac....I get nothing but warmish air! I can hear the actuator so I don't think it's sticking. If I disconnect the negative battery terminal even for a second and reconnect, start the car, nice ice cold ac again! Any thoughts or solutions? Please help!