Another trailer brakes only work with manual override on controller question

[northerly1]

I have a question concerning a Tekonsha P3 controller connected to a 2015 Dodge Ram 2500 5.7. My truck has 4 factory wires going out the dash to the P3 controller via a connector: pink/red(+12V), black(ground), green/white(brake light signal), green(electric brake feed-controller signal)

All was working but now I only have trailer brakes if I use the P3 manual override.

-all the truck and trailer brake lights function correctly.
-volt meter pink/red to black-14.5 volts(truck running)
-green white to black-14.5 volts when the manual override is used fully-no voltage when foot pedal used
-green to black 13.5 volts when the manual override is used fully-no voltage when foot pedal is used.
The controller in help mode reports no voltage out when using the brake pedal

As mentioned all the brake lights are functioning correctly. I tried a new brake light switch(3 wires to the one on this truck) and it did not make a difference, I tried swapping in a different P3 controller and it did not make a difference. I seem to get no signal from the brake light switch but the brake light works and I tried a new brake switch with no effect. Is there something I am missing? I really am unsure about exact details on how this 3 wire stop light switch with no contacts inside works and even the 2nd one is bad?

 

[Travelin Ram]

P3 is an inertial control, it will not apply brakes just because the brake pedal is pushed. It has to detect the truck deceleration using it’s internal accelerometer plus the brake pedal switch is pressed.

 

[northerly1]

Sorry I should have mentioned this applies while driving regardless of speed.

 

[Tulecreeper]

P3 is an inertial control, it will not apply brakes just because the brake pedal is pushed. It has to detect the truck deceleration using it’s internal accelerometer plus the brake pedal switch is pressed.

The ones we used back in the good ol' days when everything was much simpler.

 

[Travelin Ram]

Sorry I should have mentioned this applies while driving regardless of speed.

In that case sounds like you are right to focus on the brake pedal input to the controller. Manual operation doesn’t require brake pedal.

I’m unfortunately not had any reason to dig into a Ram brake switch. So hopefully others can be more help.

I did have a GM truck with a faulty brake switch, even though the lights worked. Turned out to have two switches in the assembly, for redundancy I believe.