On the 70 I am working on, there are 3 ground wires coming off the under dash harness.
One goes to the emergency brake. This I am sure of.

I've ran one to the cars metal dash and the other to the back of the guages. Is this right ?

This is where it gets tricky.
Should the ground on the back of the gauges go on top of the PC or under it ? Does it need to be touching the actual metal gauge housing or should it be touching the ground circuit of the PC ?

I've been searching for a wiring diagram or schematics for the 1970 round gauge dash. No luck.

Nate