Troubleshooting Brake Controller Output Pin on 2018 Toyota Tundra  

Question:

Expert Reply:

You do not want to add a load resistor like # DI34ZR to your brake controller output wire. Adding an additional power draw on that wire will not help. The load resistors are intended for adding an additional power draw on lighting wires that use LED's because there is a significantly smaller draw from LED's that can cause errors or hyperflashing.

Your trailer brake controller output will have the necessary draw on that 5 o'clock pin without any resistors. I recommend checking it by first using a circuit tester like # PTW2993 on that 5 o'clock pin and using the manual override on your brake controller. That should allow the light to increase in intensity as you increase the voltage output with that manual override. You can adjust your brake boost intensity on your controller as needed.

The manual override will be the only way to test your trailer brake output when at a stop because the brake controller is a proportional controller so it won't deliver power when not decelerating except through the manual override. When at a stop, there is no trailer braking power required, so none will show without that manual override function.

Then you will connect your trailer and test the wires at your brake magnets for the same changes. If you are not getting the power, then you know you have a wiring issue on your trailer. If you have a lesser intensity, then you will want to check the ground on your brake magnet making sure you have a bare metal to metal connection to your trailer frame. Finally, if the wiring is good and your brake controller checked out, then you will need to test the brake magnets. I've attached an article to assist.

expert reply by: Jason S

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