I have an 97 deville.My headlights no longer come on with the dimmer Switch.i have to pull the bar in and out until they come on. The parking light and the driving light come on with no problem. What could be the problem?

Sounds like it could be the headlight switch unit or the light sensor on top of the dash. I assume you mean the Twilight Sentennial no longer operates? The light sensor will be near the blue bubble in center of dash. You can try to cover it up with a cloth to simulate darkness while testing or working on the system. The headlight switch easily pops out of the front of the dash carefully with a screwdriver. Easy to find on ebay.

I too am unclear on what the problem is.
Do you mean the headlights don't work or the high beams don't work?

The headlight works only when the driving lights are on. The dimmer does not cut the lights on only the parking lights.The high beams no longer work.

What did you find the problem to be for the lights not working?