If Sanderson has a 1951 Suburban (as in Sanderson's Profile), the Headlamp Switch shown above is very similar to the one in his truck.
The Headlamp "Switch" is fused and serves a variety of functions (it is not just a switch).
1. Battery power (at all times) to the domelight and the stoplight(s).
2. Battery power (at all times) off the rear terminals (one terminal is for battery-in). I think the radio, glovebox light, turn-signals, and heater-motor are examples.
3. Switched power to parking, tail, and headlamps/lights.
4. Switched and rheostat-adjusted power to dash lights (and clock and radio lights, if you have them).
Other electrical components might receive switched or unswitched power from the ignition switch (radio-maybe, cigar lighter, glovebox light-maybe).
Tim
