Headlight short

Go down to "the parts store" and buy yourself about a 20A universal automotive breaker. Or buy a "short finder kit" used to be by KD tool and others. Wire that in series with the battery ground, then turn on the lights and go to work. The simple old school short finders work by having a needle in what appears to be a meter that is influenced by magnetic force. When you lay it near a harness that has a short problem, the needle will deflect more that less, as it will when moved away.