mystery wire and switch

[75' forty]

bought an 05 a while back, had a switch on the dash with no wires.

while working on the high idle mod i found some wires cut. it was coming thru the bottom of the driver side fire wall, traced it to the fuse box in the engine bay. wire was broken off at the fuse box. there were 2 small wires, both red that were used.

any idea what the PO had wired in?

[Tonka Toy]

Maybe an ignition kill switch but don't know why he would have the switch on the dash.

[virginiavenom]

amp kill switch