What is it that you are doing, IE chasing a problem or rewiring?
that circuit is simple. HL switch gets unfused power from the ammeter only for the headlights. Through and out the HL switch and to the dimmer. No matter which position the dimmer is in, two posts will be hot, with HL switch on, as it will be feeding either lo or hi
From there the lo or hi beam wires go out through the bulkhead connector, so more connectors that can be corroded. ANY connector, and ANY switch is suspect.
Then of course, around to the lights and two more connectors. Don't discount the headlights ground wire at the headlight area which can be trouble
