its TFI, and it runs through the harness that you burnt, which if i where you, any place that melted i would remove the covering and inspect the wiring, but it could be the TFI on the side of the dizzy,
but buy looking at the pics, i would spend the $30-$40 on a junkyard harness from another bronco II from 89
i would grab the harness from the ECU to engine compartment, and the engine harness, and a new ground strap from the engine to the windshield wiper motor
which btw with the said harness you burnt, i completely pulled that out and everything including the starter would work for my v8 swap, i just got a rubber plug where the ECU use to be, the power windows, radio, etc all work,