About a month ago, we drove home at night and about five or so minutes after getting out, noticed from the house that our headlights had not turned off. I fiddled with the switch and everything, but finally had to unhook the battery to get them off. This has happened several time since (always after the lights have been on for some time) and every time, I have to unhook the battery to get them off. The next day after unhooking the battery, I can get them to shut off and everything works great. I'm guessing that something is getting hot, but don't know where it might be.