Engine dies when parking lights are turned on.

I recently bought a 2002 Taurus and the instrument lights do not work. I pulled out the headlight switch and the one connector was off. I plugged it back in and the instrument lights now work, but the engine dies when I turn the parking lights or headlights on. I disconnected the connector and the engine runs fine again with the lights on, but of course the instrument lights quit again. Any ideas? Thanks