Headlight question

Headlights aren't working on my 68 Fastback. I believe it is the ground. I have 12v at both high and low beam. Where does the ground connect. I have grounds for the inboard turn signals that are connected to the rad support, but i cant find where the headlight ground is?? Where would it be on the OEM harness?

On another note where does the horn relay get mounted?
My fat fingers found it