Reverse light lead in '01 for back-up cam

[TGFL2GRAM]

Installing a new stereo with backup cam. Is there any wiring in the cab I can use, or do I need to pick off at the trannie and bring that back into the cab? It's an NV5600 6 speed.

Any suggestions?

'01 2500 (akchully an '02 but I call it an '01 to make life easier)