connecting to a 7 blade RV plug

[lost in space]

I have a 7 blade RV plug in the side wall of my truck as it used to be connected to a 5th wheel. I can find the ground, hot and running light connections. Is it true there is no brake light connection? Thanks for any help you can give me?

 

[Desert Rancher]

This should help. Most newer trucks have a battery charge connection that has +12V only when the key is on.

http://www.etrailer.com/faq-wiring.aspx

Welcome to WTW!

PS: now that I have woke up....did I pass out or what?

All of the light circuits are there. On some trucks, the fuse and/or relay may need to be installed.

I tapped into my trucks +12v battery charge circuit from the trailer harness and connected it to my camper battery.
It is only hot when the truck is running, as it is wired through a relay and charges the camper battery while I drive.

 

[BenG]

yes there is no brake lights, the right and left turn lights are the brake lights, you may find a spot that lights up solid when you step on the brake, but that is likley the wire to the electric brakes on your trailer connection, and won't be used on the camper. only need tail/clearance lights,left, right turn, ground, and charge, if plugs is wired for it.

 

[Mike S.]

When I rebuilt my 94 I put brake lights on the top portion this is run off the rear 7 pin plug on the Dodge as are my clearance lights. my propane bottle is partially blocking the driver side brake light. I also add a gel deep cycle battery but I add a set of #4 wires to charge it, they plug in where the old 4 prong was in the front, it has a solenoid with a separate switch. Works well and enough to keep my battery charged, I am looking at adding one of the small on demand water heaters soon.