Today we found the brake lights not working. Here is what I have found so far
None of the three brake lights function (left/right/third)
The trailer plug DOES show power when brake pedal pressed / no power when pedal released.
Brake light bulbs visually look good
15 amp fuse up front replaced (the old one tested good)
Booster pump does come on when the brake pedal is pressed (Cummins off).
There is a converter for the trailer plug. The converter for going from the three light system (Alpine tail lights) to the two light system (four prong trailer plug).
I tried to test the left tail light connector - It tested good on power for the tail light - No power for the brake light.
I did not have any strange behavior this past weekend from the cruise control. (Failure to engage or disengage).
What confuses me is that the converter is getting a brake light signal - but it is not getting to the actual brake lights?
Any suggestions on how to trouble shoot further would be helpful.