I just bought a 1990 300E and put a new battery and alternator in it. The car dies even with a new alternator. Also, when I lock the car, the battery is draining. After getting in it, I can hear a motor running (sounds like it is somewhere in the back seat area). I think it is the motor trying to raise the windows after you lock the car. I am puzzled by the car dying while driving it with a new alternator. Any suggestions?