How to Install and Connect a Trailer Brake Controller

[Jeff Kelley]

How to Install and Connect a Trailer Brake Controller
By Eric the Car Guy
Questions
1. I was a bit concerned that the power going to the brake controller was momentary, yet the power leading to the trailer connector was fused. Then, I saw the schematic and it showed the red wire was for auxiliary power.
2. The blue wire is the power wire for the brakes. Therefore, the ground to Vehicle wire, and the ground to Trailer wire (both White) are essential if you want to have brakes. I know you didn’t have a trailer handy, but people should know how important that the white wire is securely grounded to the trailer.
3. Did you discover why your back-up light connection was weak (purple wire)? The diagram shows that the wire can be used for back up lights or a Hydraulic Coupler. Either one of those would not work well with inadequate voltage.
4. This was an excellent video. The quality of the install and the emphasis on safety were superb.

Topic

[EricTheCarGuy]

The power going to the controller is constant battery voltage, wired directly to the battery. The circuit breaker is momentary. It will only cut power if the circuit is overloaded and even then it will come back on after the circuit breaker closes again. This is how the instructions stated they wanted the circuit wired.

The blue wire is actually the trailer brake output from the controller. The voltage will vary depending on how much braking is required. You might remember in the video that I went through great pains to make sure I had a good ground at the white wire which is directly on the trucks frame.

The back up light connection was weak because it was wired in series with the reverse lights. Most trailers don’t have reverse lights. It would sometimes be used as a signal to turn OFF the trailer brakes when backing up to make parking a trailer easier. It’s more of a signal wire than it is for actual lighting.

Thank you for your comments.

[Jeff Kelley]

Thanks, Eric,
Somehow, I missed your email reply in my inbox. I am not the only one using this computer, yet I shouldn’t have missed it. Too much junk, I guess. Thanks for the clarification.
Question 1 – I answered it myself. The red wire, like you said, goes to the box.
Question 2 – Was a warning to others about the white wire on the trailer end. I wanted to make sure installers knew to make sure it was grounded securely.
Question 3 – The purple wire was my question to you. I didn’t know it was a disabler. That makes sense. Wired in series doesn’t make sense to me. I’ll watch the video again, and review the schematics.
Question 4 – Was a compliment. I shouldn’t have called it a question.
Thanks for your reply. Sorry for my belated response.

[Author]

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