This is a schematic of the headlight circuit. Note that the dimmer switch is located electrically between the headlight bulbs and the headlight relay.



The headlight relay must be energized for the LOW beams to illuminate.


Likewise the headlight relay must be energized for the HIGH beams to illuminate.



The interesting thing is that the headlight relay does not have to be energized for the PASS switch position to illuminate
the HIGH beams. If you lock the dimmer switch in the HIGH beam position with key OFF, nothing happens. If you pull
the dimmer switch back in the PASS position -- even with the key OFF and the headlight switch OFF -- the HIGH beams
will still illuminate. Even if the DRL module has the LOW beams operating at 80%, the HIGH beams will still illuminate.
If you lose your keys in the woods you could use the dimmer switch to flash SOS in Morse code. The circuit so simple
but the concept is genius.