05 Silverado High beams stay on
 

My 2005 2500 HD recent has a problem, with the truck off, key out. The high beams will come on their own. I have to remove the relay to get them to turn off, the first time this happen, it killed my batteries. The combo switch was in the neutral position, and they came on. Any thing I should check or look over? Any hint would be awesome. Thanks