Trailer 7 pole harness

[Ron Davis]

Hi everyone… been a bit since posted… new found issue and trying to hit the road tomorrow….

Just discovered no brake lights at my tow harness..  flashers flash and I can get tail lights signal separate from turns…but press brake and nothing.   I noted this 96 patriot has turn (top) brake/tail (middle) and reverse(bottom).    The RVs standard brake lights work ..obviously….

anyways…frustrated
i hardwired a wire from brake bulb to the 7 pole harness (where a joined turn/brake wire would go……and well as anticipated that also activates the RV flashers when hitting brake…(bad idea) but had to try it… lol.

Saw other posts talking of a black box / duplex adapter that’s wired in to convert the multiple wires into single I guess… if this rig has it where would I find it?

anyway…  where or how does the signal for brake get joined into the flasher wires for the tow harness to work as designed.   I cannot isolate why I get flashers but not brake lights.  they run the same wire into the harness from somewhere in the RV.

Side note I have had issues with simple tail light but believe I have that worked out. As I have a 12v tail signal at the harness now.

Any help is welcome as I am running out of ideas…….. feel certain this was working in the spring….
Thank you.

[Steve Huber Co-Admin]

Ron,
No idea why flashers started when you hardwired from brake light to 7 pin brake connection. Sounds like you went to wrong wire. Suggest you first apply 12v to the 7 pin brake connection to verify it drives brake lights on toad. If OK, apply brakes (use a helper or a 2x4 to hold brake pedal down) and use a meter or light probe to verify the RV brake wire. Hooking up to this wire should solve your problem,
Steve

[Eric Maclean]

Ron
The box you are looking for should be in the right rear ( passenger side rear ) of the coach somewhere on or near the right rear frame rail inside the engine compartment .
It is what is known as a duplexer or what we used to call a foreign car converter it allows the two separate inputs turn and brake signals to be combined to drive a signal bulb.
It would appear that the one in your coach is not receiving a brake input or the duplexer is defective
The good news is you can by them at any parts supply ( NAPA).


https://www.napaonline.com/en/p/BK_7551086

Hope this helps
Eric