Troubleshooting Replacing Trailer 6-Way With 7-Way

Question:

I changed my 6 way round to a 7 Blade now I cannot get trailer brake to work. I matched up wires and everything works trailer running lights r/l blinkers, back up lights and brake lights I believe my issue is I have the 6th wire and am not sure which of the remaining two posts to plug it into. When I plug into one terminal it locks up the trailer brakes plug it into the other the other the braking system does not work. Please help I am supposed to be heading out at 4 this afternoon PST. Old Plug TM-Brn Grnd-Black LT-Yellow RT-Green AS-R New Plug TM-Brn Grnd-Black LT-Yellow RT-Green EB-Red AX-Open BUcenter Post-Open In addition this plug has a jumper with a bulb attached to Grnd and TM

asked by: Coach D

Expert Reply:

Wiring the brakes to the 12 volt hot lead would make them lock up so you need to be sure you have the pins on both connectors wired in the same way. Use a circuit tester to make sure the pins on your vehicle connector match the pins on your trailer connector (see accompanying photo) and make any necessary adjustments.

The other issues is that you may have a short somewhere in your brake wiring so you can go over the wires on your brakes to see if there are any broken, nicked or crimped wires but I am guessing the issue is you have not wired your new 7-way to match the vehicle side 7-way. Also make sure you have a good ground which is attached to a bare metal surface free of any paint, dirt or corrosion.

I have attached a couple of help articles on trailer wiring for you to look at as well.

expert reply by: Kyle S