Guages go dead, interior lights wipers and washers stop working.

under what conditions does this happen? how often?

there are a few relays for the wiper in the power dist box underhood, the fuse under dash in jnction box controls power to all three and they may not be getting any power, it's a white black wire. in the junction box ther eis abattery saver relay that may be screwing things up check thaor pull it out an dsee if anything works then. this cold also be a bad ignition switch not sending power to those circuits as well.

it could also be a loose ground, you would have to go into more detail of what is going on when this happens.