At the back of my 95 F-150 just behind the spare tire are two plugs next to each other that terminate at plastic caps attached to the rear cross member. I know one of these plugs is for a trailer light wiring harness which I put into use years ago. I assumed the other was for trailer battery charging and/or trailer brakes. I assumed this because I used to own a Chevy Suburban that was factory and/or dealer pre wired for this purpose I just had to add the components. I also assumed this because the under hood fuse box has a 30 amp fuse that says it for "Trailer battery charging" fuse #18. Fuse appears OK. This extra plug has three wires. One blue and one orange both a heavy gauge wire and one smaller gauge black wire with a green stripe. I do not see these wires in my Chilton's wireing diagrams. When I attached a 12V tester to all three wires I got nothing. What I am looking for is a full time hot wire somewhere near the rear of my truck so I can hook up a 12V light inside my camper shell. Presently I only have a light that uses AA bateries and sure enough whenever I need light the batteries are dead. If this plug is not what I was wishing it was, is there any other source at the rear of my truck I can get power from. I am not looking forward to running a wire all the way up to the battery up front if there is already something available thats a little closer.

Thanks for any help in this matter.

 

No there is no wire that is hot all the time.
If you want to you can pull out the relay for the battery charge and plug in a jumper in its place (30 to 87).
This will make the Orange wire hot at all times.
The Blue wire is for trailer brakes.
If you need a wiring diagram repost and I will post.

 

I take it I was correct, this plug is for trailer Charging/Brakes? If that is the case the differance between My F-150 and The Suburban I had, is Ford has a relay.
Is the relay for Charging? If so what action takes place (86 to 85) to power up the relay and close that connection (30 to 87) It was a long time ago when I owned that Suburban (1988 to 1998) and I dont rember a relay. All I remember was there where only two wires one sent 12V to the trailer, the other was the return that hooked up to the brake controller. If you do have a wiring diagram that would be helfull.

 

86 & 85 have current flow when the key is in the run position. Just take a wire and crimp two connectors on and push them in the two slots.
Here is a diagram I put together for a 1995 F150.

http://i54.photobucket.com/albums/g91/subford/Electrical/Trailer/TrailerAdapterFactory.gif

 

Thanks for the wiring diagram that was helpfull. However It does not appear I have the relay for the battery charger as shown on the diagram. Or at least it isnt located at the distribution box with all the other relays. Before I go further and waste my time. Would that relay be with all the others or somewhere else? I tested that plug with the engine on and still had no power. Im going to assume I have the wiring harness but not the other components. Either way at least I know there is a wire I can trace and possibly use to get 12V to the back instead of running a new one. I'll just have to trace where it starts up front. When I saw that I had the two fuses for the Trailer Battery Charger I hoped I had a working system, but apparently at the factory they put fuses in every slot no matter what truck it goes in.

 

The relay is located in the small relay box.
If you do not have this small relay box then you do not have the trailer tow package. In this case you will have two plugs near where the box would have been and just to the right of the “y” in the word relay in the photo. You will need to jumper two of the wires (Yellow with Red hash wire & Orange wire) from one plug to the other. These two plugs are not now being used and these wires are larger then most of the other wiring. There is also a Yellow wire in one of the plugs but it is fused to 25 Amps. The Yellow with Red hash wire is fused to 30 Amps.

 

I know exactly what you are talking about. I do not have the extra relay box, but I do belive there is one ot two unused plugs in that location. I will check it out tonight. Thanks