PICTURES NEEDED PLEASE

Your headlight harness goes up out of the bulkhead connecter, and routes over the voltage regulator, thru that loop, and then runs down to the side of the inner fender, then forward. It is held in the little trough with plastic straps as it runs behind the battery. From there, it may go thru a round plastic plug in the top of the inner fenderwell to the left headlight wit the rest of the harness going thru the radiator support and passing over to the passenger side headlight. That is the way my 65 harness goes, but your 66 may be slightly different. @66fs could tell you for sure!