My 2001 Blazer has a weird problem with the headlights.You turn off the engine, the lights go off, as they should. Open any door and the headlights come on and stay on, until you disconnect the battery.If I disable the drls, they go off,remove the key and open the door,they come back on and stay on.They come on and go off as they should if you don't open a door.Must be a sensor, or relay, or something. Need help.