Originally Posted by Diseasel300

Headlights should be 12V always. The high and low beam are different wattage filaments, both run at 12V.

If you only read 6V, you have a phantom voltage, likely read with a digital meter. Most likely you have a poor ground or a poor connection in a fusebox or relay somewhere. Since you have NO functioning exterior lights, I'd look at grounds or the master headlight switch first since there has to be something common with them all.