My airconditioning and heat were both working in the spring but at the beginning of summer the only heat would come out of the vents. No matter what temperature setting it was on heat would come out. It is full of freon. Some of the morning have been cold recently and I went to turn the heat on and AC came out regardless of the temperature setting. So, I messed with it and if i revved the engine for like 30 seconds heat would start coming out and when I stopped air conditioning woul start coming out. This happened no matter what the temperature was set on. But, when it is really cold out heat will not come out. I don't have any idea what the problem could be. I would appreciate any help.

 

With the engine up to full operating temperature, feel both of the heater core hoses. If they both feel hot, then the problem likely lies in the dash controls. If one is hot and the other is cold, you have a restricted core.

I am betting that you have a problem under the dash though.