Basically wondering what grounds the dash & rear lights (rear lights have power)
But only illuminate when I dedicate a hard GND from the battery

Do the tail lights need a ground harness (yearone KJ215)

I thought the dash harness would have a dedicated GND

Fuel gage is working

Thanks, Mike

Dash grounds through it's mounting screws normally. Some tail lights need a ground from the housing to the rear body panel. Best bet is check out a wiring diagram for your specific vehicle.

Well, I can make it ground no prob....
I was under the impression that there was a
harness ground for the dash.

70 RR....The rear light harness (new from year one)
I noticed this week it has a ground terminal for each brake light (4)
leading me to think there is a ground harness

I should note, that due to this cars condition
(stripped for paint) when I bought it, I never
saw 1 wire "on" the car

Easy way to tell if you need awire to ground or if the lamp assembly is body ground is the lamp sockets and how many wires they have. A dual element bulb should have three wires if the assembly is not body ground and two wires if it is body ground. If it has three wires you need a ground some where in the rear lighting harness. If it has two wires you need a good body ground lamp assembly to body and good body to negative batt. Same with a single element buld one wire is case ground two wire is lamp harness wire to ground.