Trailer hitch 12v accessory hookup?

[DragRacer68]

I've installed a 7-pin trailer plug on my coach. I pull a 28' enclosed car trailer with it. One thing I need to still wire on the plug is the (+)12v accessory wire that powers the lights in the trailer and charges my on board trailer battery. My GMC truck has this wired from the factory.

What I'm wondering is what is the easiest way to get a +12v accessory wire to this plug that is hot only with the key on and is fused? I see big 12v accy studs in the front but is there anything in the back like that?

Trying not to have to get too elaborate with a whole new relay and fuse setup if there's already something nearby I can use.

Thanks.

[Skip426]

Haven't found anything like that on my 99 chassis , and the front to rear wiring supplied, an orange and black wire, were too small to handle a charge circuit, but could be used to activate a relay if you want to go that route, with a fused wire from either battery bank.

[DragRacer68]

Yeah, that's probably what I'll have to do. Thanks Skip.