so i just upgraded my 4 pin to a 7 pin and made all the connection, ran a wire for the hot lead and e-brake lead, now i was looking at my fuse box and noticed a 20A fuse labeled "Trailer Battery" should i attach the hot lead to that? and does anyone know what wire it is coming out the back of the fuse box,
i searched but didnt really know what key words to use lol

 

If you can tell me what number fuse it is I can tell you more about it.

 

OPERATION

The standard 4-pin trailer tow connector contains the following vehicle circuits: park/tail lamps, left stop/turn lamp, right stop/turn lamp, and ground. The optional trailer towing package 7-way connector contains the same circuits as the 4-pin connector plus the following additional circuits: backup lamp, trailer battery and electric brake.


If an aftermarket electric brake controller is used, the electric brake pigtail harness supplied will make installation easier. The connection (blue 4-way connector) for the harness is located under the instrument panel to the left of the brake pedal on top of the large body harness connection. Refer to the appropriate wiring information.


The battery line of this harness may be used to charge the trailer battery. However, a battery isolation unit is not supplied and the trailer battery may discharge the truck battery while the engine is not running. The battery line is protected by a fuse or a circuit breaker. Refer to the owner’s manual in the vehicle glove box for type, location, and ampere rating of the fuse or circuit breaker.

 

I do have diagrams, but they are for 07/08 model years which have the integrated power supply.
On my diagrams I have a GY/RD wire for the fused B+ trailer connection and a PK/YL for the fused Ignition. Yours are likely diff, but maybe they aren't??? Got a voltmeter? I know it won't tell you if it's the trailer wire or not...lol But it'll tell you if the same wire colors I gave coincide with each other on your model year. I'm bettting they are diff, but maybe this will help someone else with an 07/08 model year.

 

http://www.dodge.com/bodybuilder/year.pdf

Second time in a week that i have posted this link... I feel so useful! But not as useful as the link. Just work your way thew the slections and slect all that applys to your truck, and then take a look at the wiring diagrams.
If the colours match up to what your fuse box looks like, you should be good to go.