Chevy lumina light problem

1999 chevy lumina- When I turn the headlights on it blows the dashboard light, the rear tail lights and the parking lights. The headlights continue to work fine. Have replaced the fuse. Have replaced the switch for the headlights thinking there was a short. It did not fix the problem. Our mechanic looked for shorts with no results. Cannot drive the car at night. Any ideas? Thanks.

The vehicle has DRL (Daylight Running Lights). This circuitry is simply too complex to troubleshoot without reading, and understanding, how the DRL is supposed to work. Your mechanic, also, needs the wiring diagram to aid in tracing the circuits. The exterior lights go through, and are controlled by, the DRL Control Module. The Haynes Repair Manual has the explanation of operation of the DRL and the necessary wiring diagrams. Application of both could lead to a fix.

Thanks for your prompt reply. I will check with my mechanic or take it to a Chevy dealer.