Troubleshooting Brake Controller that Turns Off and On While in Use
Question:
I have a 1 owner 95 dodge 3/4 ton with a tekonsha mark 12 that was installed in 96. Had not pulled a trailer with brakes on a long time. Yesterday pulled that trailer and got spurious red light with light brake applications on the trailer. Today I went into the system and could not even get the red light to come on. I cleaned and tightened the ground, and checked the black lead for voltage to the unit. The lower wheel is centered and the unit is reasonably level in the bracket, but there is no red light whom I do the slider. Any suggestions?
asked by: Bill
Helpful Expert Reply:
You will want to test the brake controller so that you can determine if the problem is wiring related or if it is internal to the controller.
Testing the brake controller is fairly easy. Sever the blue brake output wire near the brake controller leaving enough room to reconnect it and then apply the manual slide. Using a circuit tester like part # PTW2993, you should get output to the controller side of the wire you severed. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly also then the problem is farther back either in the vehicle wiring or on the trailer.
If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire. On the red wire you will only want power when the brake pedal is pressed.
If there is power on the red wire before the brake pedal is pressed you have connected the red wire from the brake controller to the wrong circuit. You would then need to find the brake switch wire that has power ONLY when the brake pedal is activated.
If these connections check out and the brake controller is properly grounded then there is possibly a problem inside the brake controller.
I am including a link to a video that will show you how to test the wiring on a brake controller.
