The dome lights are the only item in the headlight switch that needs grounding.
Disconnect the headlight switch ground wire and parking lights should still work.
The parking lights already work.
I'll repeat: The grille parking lights work. The headlights do too. They barely flash with the flasher button pulled but neither blink when the turn signals are tried.
The taillights light up, the flashers barely light up. The right brake light works, the turn signal does too. The left only gets a tail light but no brake lights or turn signals.
I have juggled 1157 bulbs and have seen no change. The LH sockets or wiring may be to blame. I have spares I can solder in to get it working.
There is no dome light in place. Grounding the switch has no negative effects, does it?
The dash and all that is attached to it will get restored....
I wanted to get all the stuff working before I dig in and paint it all.