After Plugging in P3 and Harness 3040-P on 2014 Toyota Tundra Brake Controller Does Not Turn On

Question:

Do I have to run the ground to the negative battery terminal of my 2014 tundra? I grounded to frame inside truck but the P3 doesnt turn on. Help!

asked by: Trevor

Expert Reply:

You should not have to run the extra ground wire on brake controller harness # 3040-P to the negative battery terminal on your 2014 Toyota Tundra. You will need a clean bare metal location though. No paint or aluminum either. A bare steel surface.

Use a circuit tester such as # 3808 if needed to test the black wire after the controller is plugged in. If there is power on that black wire but the controller still does not turn on then there is something wrong with the controller and it will need to be replaced.

You might also want to check to see if all of the fuses/relays are installed. Use the truck owners manual to find the locations of the fuses and/or relays related to a brake controller and/or tow package wiring to check them.

expert reply by: Michael H