Help needed with A/C. Symptoms: swithes work, A/C button and light come on, blower motor works, fuses and relays good but no power to compressor (new compressor). My guess is, there is little or no freon in system. How do you get freon into system if the compressor doesnt come on? Dont the compressor have to cycle in order to pull freon into the low pressure side of system? Where is the low freon switch that keeps the compressor from coming on? I have not checked that yet.

 

What you just posted, my suggestion (strongly) is to take it to a shop. You add freon to the low side with it running. Look around the accumulator on a solid steel line for a shrader valve. There will be two, suction (low side), and discharge, that will be the smaller of the two valves. Did you replace anything other than the compressor, and did you recover the system?

 

I just bought the truck, the po had a new compressor put on a few years ago. He hasnt used the truck the last couple of years. I went to add freon to the low pressure side with engine running and A/C on. As it took the freon, the compressor began to cycle. It wont stay on as I only added not quite a full can. When I removed the charge hose, i noticed that there was a small (very small) leak at the shrader valve, even when I put the dust cap back on. I could not remove or tighten it because it sits too far in at the connection. Not sure if a fully charged system will stop the leak, or should I change out the valve.

 

Is it removable? You might try some dyed freon to find if it is still leaking, or elsewhere in the system.