’03 chevy 2500, back up, interior lights

'03 Chevy DMax 2500 Crew cab. Back up lights do not work any more at all. Interior lights only work off push button on overhead light.
Perimeter lighting is set to on, and front and side lights work as expected, no BU lights or int lights. BU lts do not work in reverse either. I believe this all happened at the same time so it is all the same issue. All bulbs/fuses are checked and ok.GM dealer was not able to fix.

I find that VERY odd for a dealer not to be able to find the problem. Did they tell you how far they diagnosed the problem or anything they did?? If you have no backup lights the first thing they should have done was scan for DTC's. Not having reverse lights will set off a DTC. That should have been the first thing they checked. Also they should have tested the backup lamp supply voltage circuit for an open or high resistance. These are all standard things for a place to start looking. The reverse lights and interior lights both run through the BCM so you could have a problem with that too. But again those are all things they should have checked. Unless they are hiring untrained non-certified mechanics off the streets now lol....

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DIESEL

I too thought they should be able to correct the problem, but they did not have a lot of time when I had the vehicle in their shop. There are no codes set and they did check various circuits. No solution. I have posted in other sites regarding this issue and have had 2 calls from others with the same problem. Will be back at the dealership in early Jan '09. Any other ideas ?