Anyone know Ford headlight wiring???

Hoping to get this sorted out tonight...

Working on the '66 Galaxie tonight and no headlights. I get voltage at the lights for high and low. Problem is no ground though the plugs. When I bypass the ground with a short wire directly from the back of the plug to the rad support I get lights.

Not sure where these ground wires go to and don't want to cut the harness wrapping to trace. I figured maybe grounded through the headlight switch and tried grounding the switch body via heavy wire to a good known ground (firewall). No dice that way. Any thoughts?

Want to drive it to cruise night Friday but need headlights for the trip home. Thanks!!

FYI the taillights and brake lights work fine. Still can't find the ground. I tried tracing continuity to the plug in the firewall and can't get continuity on any of those 6 wires in the plug to the ground wire at the headlight socket. There are 2 others that branch out fmor that plug into individual plugs that didn't have continuity to ground of the headlight plug eitehr. Also 2 sipped wires from the harness o the drivers side right behind the headlight and washer fluid pump. No continuity to those either from the headlight plug ground wire.

Seems to indicate to me that there is a break in whichever wire is ground in the harness on the engine bay side. Wonder if a '68 harness is plug'n'play? I have like 2-3 of those. I'm gonna check. Any ideas though? Should I just ru a new ground wire from this harness to the battery?

Any that I have worked on have the ground wire from the headlight socket wire to ground somewhere on the rad support. My 71 has a ground from the harness on both sides. If you cannot find it right away just run a tempory wire to the body. You can splice it in the area that is covered with tape so you can repair it later and not see it.
Don

'68 harness is different, and I seem to have 1 full wiring harness for an entire '68 and various other parts of harnesses frmo other '68s. Still have 8 wires going through the firewall on the '68, but all 8 are in two larger plugs instead of 6 in a larger plug and 2 individually in '66. I see nothing like the two snipped wires on my '66 harness in the '68 harness, os no clue where those should go. Also, the '68 headlight harness has a small wire for ground to the rad support. No indication that was ever present on the '66 harness I have. Thoughts?

THanks Don, I had to cut away a little of the wrapping on the harness to find the ground wires. Extended and attached to rad support. Drivers side headlights now work, nada on the passenger side. Continuity fmr ground to socket plug though. Maybe bad bulbs?

Both the front high and low beams are connected in parallel with each other so the problem could be a bad bulb or socket. Of course depending on where the original ground wire is broken you might have to add another temporary ground at the other lamp. This would be the case if your harnass only had one point of ground for both lamps. A meter or test light would come in handy here.
Don