dash lights not working

1971 Rallye dash:
I have dim dash lights and posted about it before in other threads.
I went about hooking a ground wire off the headlight switch and the right side board but still the same issue.
All new 194 bulbs and even new sockets.
My question is where EXACTLY do I need to attach an external ground?
Is it just a matter of any circuit board mounting stud or is there a specific area.
My radio lights up nicely I assume because it is properly grounded.
Pictures would be most helpful.
Thanks Ron