Power for ONLY the headlights comes from the ammeter harness directly TO the headlight switch. With switch on, power goes down TO the dimmer switch. This is a simple 3 terminal SPDT switch, that is, two terminals are always connected, and when you mash the switch, the power and the "was dead" terminal is now connected
One out for hi, and this branches off to feed the high beam indicator
One out for lo
both these wires then go through the bulkhead, out and around to the headlights
