Harley headlight problem, any ideas on the cause?

I have a 2002 Super Glide. Last night when I was out riding it I put on my high beam. I switched back to the low beam, no problem. I turned on the high beam again and not only did I not have a high beam, I lost my low beam as well. That's right, no headlight at all. When I switched back to low beam the low beam did come back on. This morning I was riding my bike and the low beam was on. I got home, turned off the bike. A few minutes later I decided to investigate. When I turned the key on I found I had neither a low or a high beam. I took off the headlight. I found the connection the light plugs into was melted in the area where the black wire connects to the connection. I spent the afternoon trying to chase down a possible short but came up with nothing. By the way, all the other lights on the bike continue to work. Any ideas on what caused this? I try to do as much repair work on my bike by myself, but electrical is one of my weaknesses.