I have a 2007 Silverado 1500 Z71 (new body style), and I am having trouble diagnosing the driver side power mirror. So, the problem is that it will adjust up and down, but not side to side. I've replaced the mirror switch, same outcome. I ordered a new mirror, and same outcome. Has anyone ever come across this problem? I checked the wiring harness, and could not see any obvious defects. Any advice on this would be much appreciated!