57 Head Light switch explained - TriFive, 1955 Chevy Feb 29, 2012YELLOW 20 GA wire is connected to the head light dimmer switch. This switch feeds the high and low beams. The high and low beam is controlled by the floor dimmer switch located on the left upper floor and operated by the foot. ORANGE 18 GA.57 Chevy Color Wiring DiagramsMay 04, 2019Brake light switch wiringNov 18, 2015See more results 57 Headlight Switch Wiring | Classic Parts Talk Jan 06, 2015Similar wiring issue.. I have an issue with my wiring on my 57 3100. Is there anyone out there that may have a picture of the original wiring of the ignition switch and the light switch along with the gauge cluster? There is a brown wire that comes out of the harness that goes to the gauge cluster, and I cannot figure out where it goes.