Since your post is 2 months old I assume you have taken care of the problem by now. For others that may have the same problem in the future I will give a little info. When your breaker trips as soon as you turn your AC on, there is most likely a direct short somewhere. Since anonymous has disconnected the cable from the disconnect and it no longer trips the breaker, the short is in either the cable or the outdoor unit. You would need some knowledge of electricity to troubleshoot this problem. I would expect any 4 year old unit to still be under manufacturers warranty. Manufacturers warranty covers parts only. Service calls and labor are NOT covered by manufacturers warranty. Don Garage Door Opener Guide