I recently installed a Kenwood Excelon KDC-X979 in my 99 Blazer, and it ws working great until this past week. When I first start the car in the morning, the unit turns on, like it's working normally, but then the top face plate slides back into the unit and the bottome face plate sits at a 90 degree angle and it loses power. If I try and hit the power switch, it tries to reset itself and goes back into the 90 degree position. Anybody have this problem before?