Power runs from the battery (red wire) thru the fuse to a red/purple wire, which goes to the ign switch. When the ign switch is in the run position, power is supplied to the purple wire. The purple wire will power the gauges, so trace it out. Look for some kind of short circuit on the purple wire. Look for rubbed off insulation, melted insulation or a spot where the purple wire is pinched or broken. Sometimes gauges can internally short, but that is rare.
