Bill 10/14/2010Find the fuses and check them. If there OK, check the ground connections. Those are the black wires coming from the headlights to a metal screw going into the body. The screw just holds the ground wire up against the metal of the body. Don't forget to get the body nice and clean where the wire touches it. Use some fine sand paper or emory cloth and shine them up good and re-attach them. That might do it. After that, you might want to try a new headlight switch. It has a circuit breaker in it that may have blown. I have a 1985 Silverado that's going through this same sort of problem. Hope you have better luck than me.