wiring for rear view back up camera and trailer hitch

1. I need to know what color is the positive REVERSE tail light and what color is the negative.
2. is there a hidden wiring harness for a trailer hitch? If so where is it. If not can some one put me in the right direction to wire a hitch.

Both for a 2500 144" 2008 sprinter. thanks

Do you have a digital (or analog) Volt Ohm Meter (VOM)?
That is the best tool to trace out wiring.
As far as the trailer wiring, I do not believe that the NCV3 comes prewired for
trailer towing unless you ordered it that way.
You can order the factory wiring harness and install it yourself.
The harness is pricey, but if you install it correctly, it will not cause any
problems with the Sprinters electrical and electronic systems.
The factory harness comes with very detailed installation instructions.
Takes about a half a day or more to install correctly, but after installing
mine I've been very happy with the result.
If you tow a larger trailer with electric brakes on more than one axle, I
would recommend adding at least 1 #10 AWG blue wire to handle the
additional current more brakes will need.
Hope this helps,

Spp112,
Search and ye' shall find. I used the search in the blue bar above. Of course it helped that I remembered part of the thread title.

Trailer Wiring OEM Harness vs. Light Module
https://sprinter-source.com/forums/showthread.php?t=7328&highlight=oem+trailer+wiring

You can find more threads by using "trailer wiring". Have fun. vic