Before you do anything, replace the battery in your key fob. I was having this exact issue (driver door handle entry button would not work, but all other buttons would work fine). I did some on line research, and replacing the fob battery was recommended. The reason given was, apparently the receiver for the fobs is located somewhere near the passenger rear wheel well, and the drivers door handle is thereby the furthest away. Weak fob battery = weak signal. I replaced the fob battery, and presto! no more issue with the handle button. Prior to replacing the battery, the fob still worked fine and would auto start the vehicle, unlock doors, open the lift gate etc., it apparently just didn't have enough juice to allow the exterior door handle button to work on the driver door. Try replacing the fob battery, see if that solves the problem.