Action Taken When the DTC Sets: U1512
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
No window on the specific side of the vehicle will operate if the open is before the first splice from the door module, and both DTC U1511 and U1512 should set. If open after the first splice, the individual window will be inoperative and a single DTC should set.