Looking for someone who has who has installed a different gauge cluster

I haven't found a wiring diagram for the light switch.....

Ian, LOL, you've got to sit down and learn to use those diagrams

Look in the index, pages 14-12, 14-3, "Headlight switch" is 26C

Go to 26C, and there it is

Notice that the wiring is all labeled "CI--35" which again, is the connector

L1--12BK is main headlight power coming into the switch, "B1" or "Battery 1"

L8-18P is tail/ park/ dash lamp power coming in from the tail fuse, "B2" or "Battery 2"

D---bottom left is the switch ground for the dome lights when you twist the dimmer knob to the left

H-- the light green is headlight power going out to the dimmer switch

R--originally meant "Rear" or tail lights. This now feeds both park and tail lights

Far bottom right, E1-20T (tan) is dimmer controlled dash lamp power. This goes to the fuse panel, through the instrument fuse, and then turns to orange and feeds out to all dimmer controlled dash lamps