It could be. What you're looking for is any black wire in the harness that might be exposed and touching bare metal or and green wire plugged into a black. Those are the most common scenarios. If it were me, I'd start at the main fuse and start measuring for continuity to ground. Assuming your headlight isn't an always on style, you shouldn't get any reading. If you get a reading of less than an Ohm or so, you definitely have a short.