Auxilliary t/g window switch circuit for '78-86 Broncos. This design is fairly simple, but requires long splice wires (due to the factory routing), and creates extra resistance in an already-stressed circuit. For a VASTLY superior modification to '87-96 Broncos, see:
Note that the internal circuitry for the dash switch is specific to '78-86 Broncos.
To add a simple self-diagnostic capability, wire a 12V lamp across the latch safety switch terminals, and mount it in the tailgate shell above the lock cylinder in the inside sill (through a carpet retainer hole if present). If either control switch is activated, and the only thing preventing the glass from moving is the safety switch, the lamp will light and be visible to a person using either switch.
