Hello, i'm in the process of putting my car back together and last night I put the grills, bumper, ect.. in and I put the headlights and high beams in.. I turn the headlights on and all 4 go on, so I push the high beam switch, I see the high beams turning on and off in the headlights (outer bulbs) but the high beams (inner bulbs) never go off. The only way I can get the the high beams to shut off is if I unplug the wires from the bulbs... The car has the original harness, (it is in great condition, so I left it alone) and a brand new high beam switch.

I'm not sure I totally understand but if you are getting the lights to go on and off with the high beam switch, just the wrong ones (outer) then it sounds like they are wired backwards. If you just flipped them wouldn't everything be right... again sorry if I am misunderstanding?

The plugs are different, so it would need to be the switch wiring. You can't plug a low beam lamp into a high beam plug.

Correct. But if it was all apart and the harness was put back in backwards at the lights... wires may have been spliced etc as opposed to unplugged? How apart was the car? Was the dash apart?

Common problems with lights are lack of good grounds. Double check you grounding of the harness. There are specific gnd wires on the harness for head lights. Also make sure frame grounds etc are connected. Do you have Batt grounded to RH fender and engine block?
Light switch needs to GRD to sheet metal.

Could it be that the low beam bulbs were installed inboard and the high beams outboard by accident? The metal bulb "cups" can be installed in the wrong locations.

I did that the 1st time.

FYI: The headlight dimmer switch has its own unique ground into the floor pan next to the switch itself.

The lights are not going on and off with the switch. The high beams (inner bulbs) stay on when I hit the floor switch. The headlights (outter bulbs) Are 3 prong and are high/low beams, when I hit the floor switch the outer bulbs/headlight bulbs switch between low beams and high beams.

The plug are plugged into the correct bulbs. 3 prong to outer headlight bulbs and 2 prong to inner high beam bulbs.

The grounds on the headlight harness are grounded properly, the battery is grounded to the right fender and the block, the block is grounded to the frame and the firewall. The headlight switch is mounted to the dash and the high beam switch is screwed into the floor, is there another ground on the high beam floor switch besides being screwed into the floor??

The bulbs and cups are in the correct spots. Inner, 2 prong, outer 3 prong.

Does the floor switch get another ground besides being screwed into the floor??

Bear in mind that it's been two years since I have actually seen my car (and my floor pans were bare up to it going to the paint shop), but I thought I remember a ground pigtail wire that came off the wiring harness connection to the dimmer switch that screwed into the floor near the switch. I thought that the mounting screws for the switch itself were NOT the ground for it.

No

The dimmer switch, floor switch, doesn't have a ground. All it does is switch the current path to the different lights, high or low, and to the high beam indicator in the dash. Juice goes from the headlight switch into the dimmer switch then out to either the high or low beam wires to the lights and then the circuit grounds after the lights.

Real simple circuit, high beam wire out of the switch, green and black on a 68, to the outer and inner high beam lamps then to ground. Low beam wire, black and tan on a 68, out of the switch to the outer low beam lamps then to ground. The low beam wire goes to the left high-low pigtail and from there to the right high-low pigtail. The high beam wire junctions near the left light and from there one wire goes to the left high-low pigtail, one wire goes to the left high beam pigtail and the third wire goes to the right high-low pigtail. A wire goes from the right high-low pigtail to the left high pigtail.

Check that the wires and connectors at the high-low pigtails aren't somehow shorting from the high to low circuits, that would have all the lights on with either high or low selected.

Maybe your dimmer switch is faulty. Mine was corroded and the wires in the connector were touching so I had power to all the lights no matter what position the switch was in. You could take off the switch and test it for continuity from the power-in connector to the high and low connectors, and check that the switch isn't connecting both high and low to the power source at the same time. If the switch is good you have some wires crossed in the harness.

Great! Thank you!!