Troubleshooting Brake Controller Output Pin Showing 13 Volts

Updated 03/20/2019 | Published 03/19/2019

Products Featured in This Question

Redarc Tow-Pro Elite Brake Controller - Dash Knob - Off-Road Mode - Up to 3 Axles - Proportional

(1727)

$290.00

10 Gauge Wire - Blue Primary - Per Foot

(108)

$1.61

Dielectric Grease for Electrical Connectors, 2 oz.

(1503)

$11.93

Hook Probe Circuit Tester

(66)

$14.45

Question:

Hello! What voltage should you have at the trailer connector between the ground and the blue brake wire when the vehicle is running and not connected to the trailer. Mind is showing 13v. Please help!

asked by: Heather H

Expert Reply:

You shouldn't have any voltage on your brake controller output at the 5 o'clock pin when the brake controller isn't engaged. It sounds like you either have corrosion completing a circuit, a short that is drawing power from another feature, or your brake controller is installed to the hot side of the brake light switch versus the cold side.

To start troubleshooting, I first recommend using some sand paper or steel wool to clean all the pins on your 7-way. Then use dielectric grease # 11755 to give you protection from moisture and debris at that connector. Next, I recommend using a circuit tester like # PTW2993 to test your 5 o'clock pin at your 7-way. It will be a bright light when connected to 13v but shouldn't be getting a light at all when the brake controller doesn't have the manual override engaged.

If you still have the 13V, then cut the blue wire coming from your brake controller about 6 inches behind the unit and test it there right behind the controller. If the power isn't present on the wire when cut coming from your controller then you can test the manual override on your controller to give you power when engaged and no power when disengaged. If that solves the issue, then simply run a new wire # 10-1-1 to the 5 o'clock pin on your 7-way.

If that doesn't solve the issue test the red wire coming into your brake controller by probing through the insulation with your circuit tester. If that is hot when not hitting the brake pedal, then that wire is not connected in the correct spot. Use your tester to determine which wire on your brake light switch is only hot when the pedal is pressed and splice the red wire into that location. If the red wire is correct and there is power on the blue wire when cut then the controller itself is bad.

I've attached a couple articles to help further.