1985 D150 "Mr. Curtis" race truck with a 2015 6.4

HEADACHES IT IS GIVING ME!
Honestly, what they do to generate the fault signal for the tail lamps is not too complicated.
BUT:
I can't have more than 0.4 amps on the park lamp wire, which is why the BCM shut it down all the time.
Was not a problem with the fault signal, but with the amps an incandescent bulb pulls... so this will have to run a relay instead.

The fault signal is generated for the turn signal/stop light, not the park lamp.


I tore into the headlight assembly as well and it's more complicated than that. And also a tighter packed board, which is annoying because it's harder to trace out.