"Standard" Wire colors to the controller (Tekonsha and others):
- Black, Battery Positive to controller
- White, Negative Ground for Controller
- Blue, Brake feed from controller to Trailer plug at back of truck
- Red, tap into truck Brake light switch signal to tell controller to apply brakes
Remember, the above colors are just a GUIDE. your colors may be different, read the instructions! I have seen many factory harnesses that have a extra wire for dash lights (usually brown). Most controllers do not have "dash lights" so don't hook that wire up.
We used the black wire has 12 volt feed. This brake wire runs both through the firewall to the brake controller, and to the rear of the truck to the trailer plug.
We use a "side tap" to connect the 12 volt power from the circuit breaker to this black wire. This then provides a 12 volt power both to the controller under the dash, and a AUX 12 volt power feed to the plug at the back of the truck ("black" terminal)!
We then used the white wire as the "Blue" wire, as the brake controller output to the plug at the back (we just "pretend" the wire is blue, connecting it to the "blue" plug terminal and the blue wire out the back of the controller) as I do not have double jacked wire that is black and blue wire.
Remember, this is just a example of how "I" did it.
I don't claim it to be the right way, and your results may differ. It is just free information you to see and how you use it is up to you.