I have a 1983 Chevy S10 pickup. With headlights off all gauges work normal. When you pull the headlight switch on all the panel lights except the windshield wiper switch locator light never turn on and all the gauges lose power. Also both turn signal indicator lights and high beam indicator lights in the center of the instrument cluster come on without signaling a turn or switching to high beams. All exterior lights and turn signals work normal all the time when headlight switch is pulled on or pushed off and when high/low beam switch is actuated with headlights on. So you can drive the vehicle but you have no intrument lights or accurate electrically operated gauges with headlight switch pulled on. When you go to headlight high beam with the head light switch pulled on the high beam indicator light goes out which is opposite of what it should do. This problem appears to be temperature related as all lights and gauges will begin to work occasionally when the headlights have been on and the vehicle has been driven for a long time with the heater on and the cab gets very warm. The problem seems to only occur when you first pull out the headlight switch and if the lights and gauges do come on they never go off. If you turn off the head lights at this point when all gauges and panel lights have been working the gauges never lose power and work normal as described in the beginning.