Headlights stay on all the time

My 2001 blazer suddenly started keeping the headlights on all the time.Start it up the lights come on.Turn it off the lights go off.Open the door to get out, the lights come back on and stay on.Only way to get them to go off is disconnect the battery. Tried the overide button 4 times in 6 seconds.It turns them off, open the door to get out,they come back on.Sometimes when you turn the switch off, the lights only blink, instead of turning off.This is crazy.I am talking about headlights and taillights, not just the DRLS.This morning I connected the battery.They didn't come on, so I thought something had reset and fixed it. I tried to start it, and it wouldn't start,but the lights came on shining brightly and had to disconnect the battery again. Now I'm going crazy.Help:runaround:

I just wanted to let you know that I solved the problem with the headlights.I discovered, by accident, that the rear hatch was not closed properly. I closed it securely,boosted it to crank it,let it run about ten minutes,turned it off, cranked it back up, turned it off, and I've been driving it all weekend, and lights work as they are supposed to. I think it goes into a battery protection mode when something is left on, and you have to correct the problem,rear hatch not closed, then disconnect the battery for about 30 seconds, then reconnect it to reset. Anyway, this has apparently fixed my problem.:tongue: