Is Normal Brake Controller Wiring Have Three Heavier Gauge Wire and One Lighter Gauge

Question:

I have a 2023 Thor MH with an E450 chassis. I found your helpful pix on finding the brake controller plug behind the coin tray. The plug looks like it will fit your adapter but 1 wire is a small gage. There are 3 wires maybe 12 gage that are blue, red and black. The 4th is a small gage brown w/purple stripe I have pix if that will help. It should be white, maybe not a B/C plug? Thanks!

asked by: Dave S

Helpful Expert Reply:

What you are seeing is normal. There are three brake controller wires that will need to carry more current so they will be a heavier gauge wire and those are ground, 12 volt power, and output to the trailer brakes. Then there is one wire that is just a signal wire which doesn't need to carry a lot of current. That is the brake light signal circuit which is basically what tells the controller to start activating the trailer brakes.

expert reply by: Jameson C