94 shadow dash electric prob

Hi,

the dash in my 94 shadow recently started acting up, it is intermittent
but becoming more frequent. I noticed this first at night when turning
on the parking or headlights.

When moving the switch to turn on parking lights, one or two background
dash lamps won't light. The temp gauge is pegged full on as is the gas
gauge. The tach goes dead. The voltmeter is pegged to zero volts.
Adjusting the dimmer switch moves the gauge readings, when at it's
dimmest setting I can bring the gas and temp gauges off of being fully
pegged. The speedo becomes fixed at a speed and moving the rheo moves
the speed as well. Turning off the lights, everything goes back to
normal but the voltmeter reads lower than normal.

The headlight switch was getting flaky (the rheostat was dead except
for max brightness) so when this started to occur I went ahead and
replaced the switch. Not the problem of course.

Appreciate any advice Thanks!

Many thanks, Mike