2010 GMC Acadia Driver side window working intermittently

The driver side window doesn't work all of the time. No apparent pattern noticed. Sometimes on the express up feature, the window will go approximately half way up and stop, then you have to fiddle with the switch and it will go the rest of the way. Sometimes the window won't open or close and then a few minutes later it will work fine. Dealership stated that all the wires looked fine. All other windows work fine from the driver's control and at each individual window switch.