The passenger side headlights on my 68 coupe are out when I go to high beam. The low beam lights work fine, although appear weak. Replaced high beam light, but problem still there. Did research. Do I need to install relays and/or do I have a short? Where to look?

Paul

I would check the dimmerswitch, but then again you say only the pass. side light goes out...

ground

That's what I like about Vikki, to the point!
There are 2 ground connections in the headlamp harness both go to the radiator support start you investigating there.

Thanks, checked grounds, both are secure to radiator support. I'll try the low beam (these lights are fun to put back together)and see if anything is loose or cut.

Paul

If it's not the ground it's in the dimmer switch. I had the exact same thing at one time. Turned out to be the dimmer switch...

Maybe you need to replace it with a "brighter" switch.

Checked the low-beam and found a cut wire (going to high). Fixed wire and now I can see the light! Thanks again for your help.