this is a P71 with about 113000 miles, no auto lamps or DRL. At first i noticed when i turned the key to the on position before starting the car, my headlights, tail lights, and all exterior lights would come on. not every time but just about every other time. but now something is draining the battery while the car is turned off. If i unplug the negative side of the battery when i park the car, then it starts right up the next morning. If i unplug the headlight switch and leave the battery hooked up, the battery doesnt drain while parked overnight. is this a bad headlight switch or LCM relay sticking?