sorry if this is wrong thread.. It is an electrical issue.. Ive almso killed my battery from this.. I shut off my car... Take out keys turn off lights etc.. I hear a loud buzzing noise from front end and my headlights are on!! But dim... Upon opening the hood and looking straight down located just under the hood latch is what looks like a relay... Has 4 wires i think, says 12v... 87 amp.... This thing was buzzing and vibrating very loud... I disconnected it and buzzing stopped and lights turned off... Next day i plugged it in an no noise... Few mins later i heard it again faintly and lights came on... So i unplugged it again and have left it.. Also charged my battery because it was under 25 percent... There was some corrosion and water inside this connection... Could this be the prob? Really need help becuase i cannot connect the headlights without them coming back on after i exit the car... Also i have 10K HIDS... Been close to a year with no probs..

Sound like a bad relay, try replacing the relay that was buzzing.