what kind of a/c is it? probably a coleman mach 1 would be my guess. If it comes on and doesnt cool it could be out of refrigerant which means probably you have to replace a/c. There is a little relay box under the shroud that could be bad and they are replaceable. Also the compressor could be bad on it. The control board could be bad under the cover inside the R/V. I would start by pulling the top cover off and seeing if power is getting to the compressor. Shouldnt be over about 11 amps if it is getting power