is the dealer the only person that does this?i would like to get the trailer lights feature turned on,ive added the chassis harness and underhood fuse block but the bcm is not powering the relays so no power to the turn/stop lights in the 7 plug socket at the bumper.....................................ed

 

I think there's kits you get that plug into your van's tail light wiring, and you have to run your own power.

try hopkinstowingsolutions.com

 

Some upfitters and auto electrical specialists do programming.

 

The dealer can certainly program a new BCM. However it's my experience, they do so using your VIN. As such, you may not end up with the trailer wiring feature with the new BCM. Might consider using external relays wired into the fuse block under the seat.