Sherry Newacheck

I have a 2002 gmc diesel truck. I had my truck worked on for ac. The actuator was replaced 2 times before I gave up and took it to the mechanic. They had the same issue when they replaced it. They then unplugged the battery over night and it worked. But then the starter went out. Disconnecting the battery to change the starter messed everything up again. It will blow air just not cold air. Can it be reset without sending it to the mechanic again!?