The symptoms say this is a power problem, of course. So,
Did you check the fuse panel for your das gear? It is usually under the dash but every manufacturer places it in a different area, but check that it has power to it and that its fuses are all good.
But, I suspect that you have a power problem in your fuse/relay box that is in the engine compartment.
If you have a multimeter, you can check where you have 12-VDC and where you don't.
Your backup camera should be powered by your COACH battery and the under dash fuse panel. Your turn signals, brake lights, and windshield wipers should be powered by the engine battery via the underhood box.