headlights are not working . ground issue ? 1973 dart slant 6

L9BK is the common ground for the HL.

Ok . I put an alligator clip lead , one end on the ground blade of the driver side HL ( still connected ) . I put the other clip on the bumper and both of the headlights came on . They are working properly . High beams come on .

I would like to try to find and fix the bad ground if its possible . I just don't know how to do that . Any suggestions ? Also , i don't know if its related because the previous owner messed with some things , but , it appears that none of the dash cluster lights come on . i will double check this when night comes . Definitely no high beam light and definitely no turn signal lights . He bypassed the ammeter . The temp and fuel gauges operate , but unknown if accurate . I will start with changing bulbs , but doubt all of them blew out .