Coleman Heat Pump compressor not starting
Hi, first off please forgive me if any of my terms are not accurate, as i am a little new to messing around with these things. That said, I have a Coleman unit that was installed about 4 years ago in my house. I have been having problems with not so cool air coming out of the vents recently. Further inspection revealed that from time to time the compressor (outside unit) was not coming on, I could hear a click from the contact switch, but the solenoid was releasing the switch and not holding it. I can press the switch in on the contact switch with a screw driver and make the compressor come on, however, the switch will not hold in and once the screwdriver is removed the switch turns off. I replaced the contact switch assembly, and this did not resolve the problem. I have checked my high voltage line at the main breaker, and am not tripping this at all. Is there possibly some sort of internal reset that is tripping etc... I'm lost, as there does not appear to be too many parts on the inside of this thing to go wrong.
Any advice would be greatly appreciated.