[VetteVet]

If you noticed when you replaced the dimmer switch on the floor, There were 3 wires going to it. A blue wire, a tan wire, and a green wire. Those are the three wires that power the bright and dim headlights

When you pull the headlight switch knob all the way out. You should see 12 volts power on the blue wire and the dimmer switch directs this power to the green wire for the high beams, and to the tan wire when the low beam is selected..

The power gets to the lights and goes to the elements and into the radiator support to battery ground. If you have power on the blue wire and none of the lights work then I would jump between the blue wire in the dimmer switch plug and the green wire to see if the brights come on. Then if they do, or don't, come on, then jump the blue and tan wire and see if the low beams come on.

If none of the lights work, then they are all burned out or the grounds for the lights, are not making good connection to the radiator support or the battery negative.