Either I'm an idiot or the info is just not out there. I just picked up a '17 Express 3500 15 passenger van, was an Enterprise rental so it has no trailer wiring setup at the rear, just the set of taped up wires under the dash that I've seen in other posts. What I haven't seen is anyone explain where these wires terminate at the other ends?

 

Because they don't. These have nothing to do with trailer lighting. Your only hope is a supposed harness above the spare tire. But I never found it on my '16.

So, how much weight are you planning on towing? If it is substantial, you might want to look at this;

https://chevroletforum.com/forum/exp...rential-88338/

 

Ok so to be more specific, I need to install a brake controller as well as the wiring for trailer lighting. Just wondering if I should screw around with trying to figure this out anymore or just run all new wiring for everything from front to rear. I know for certain that there is no wiring at the rear of the vehicle for anything trailer related.

 

Yeah those colors don't look right.

Search around the frame, or, I've seen them tucked on the rear pillars before too (under the trim, near tail lights).