Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
Hi. Does your car have dual temperature control? If so, does it blow out hot on both sides or just one?
The most common cause for what you have is the air temp actuator going bad and not changing from hot to cold. I have not seen slamming the dash or door cause it to work before. Even though the actuator is the most common cause you may have a loose connection in your case. Possibly at the hvac control, or the actuator itself.
But I think it would be worth replacing the actuator to start with.