Dimmer switch causes gauges to peg max!?

When I saw "dimmer switch" in header my mind went to the high beam low beam switch. But away... I just remembered a case from a few years back where a member had similar faults. The dash wiring harness was held up above the instrument panel with metal strap(s). A strap had chaffed through wires. A fuse blowing short wasn't present but 2 wires were burned/shorted together. Good luck with it.