Remove the new bulb to clear your conscience(sp?) and test the system to see if the battery stays charged. My guess is that the bulb went out as a result to a spike in the system that is now causing your flat battery problem. If the lights are off at night and the battery is dead the next morning, your problem must be somewhere else. A bulb will draw power only when making light. Once the battery is damaged, it dies easily. Check the voltage when you park it and again prior to starting in the morning. See if there is a draw. Could be a quirky door jam switch. I had a lock cyclinder that randomly kept trying to lock on a Volvo and would kill the battery. Took me and the dealer 3 batteries and 2 alternators(that never needed to be replaced) before I overheard the sound one night as I walked by the car on the way into the house.
