Responding to requests for an internal wire routing diagram, following is a marked up photo explaining electrical flow from the power source to the bulb in a Unity spotlight:
1. Incoming voltage powers the switch through the wire entering the side of the handle housing.
2. When the switch is energized power is transferred through a spring loaded contact on the front of the switch into –
3. The handle end of the “rod”, in the rod and gear assembly. Power is transferred to the other end through the core of the rod -
4. And continues into the shell by another spring loaded contact riding on the bearing surface in front of the gear. This feeds through the headpost to a probe on top –
5 Which protrudes into the shell assembly. The wire that connects to the positive bulb terminal slips over the top of this probe after the lamp is assembled.
The only actual wire anywhere in the spotlight is; A - into the switch, and B - out from probe #5 to the bulb itself. The lamp assembly is free to move in any direction since there is no internal wiring to bind on rotation. The ground side of the electrical circuit is handled by a wire riveted to the shell, which in turn grounds through the body mounting bracket(s). Smaller lamps like fog lights have a brass strip that connects the negative bulb terminal to the edge of the lamp shell. This brass ground connector can be seen in the 3rd photo in post #17 above (on the left side in the photo).
