What was found
(CAN) A SHORT PERIOD OF TIME AFTER THE AIRCRAFT WAS PARKED, THE ANTI-COLLISION LIGHT APPEARED TO BE OPERATING. IT WAS THOUGHT THE MASTER SWITCH WAS LEFT ON. THIS WAS NOT THE CASE. THE NEXT MORNING, THE AIRCRAFT COULD NOT BE STARTED DUE TO A WEAK BATTERY. IT WAS REMOVED AND SERVICED, REINSTALLED. FURTHER INVESTIGATION REVEALED MASTER SWITCH CAN BE ACTIVATED BY RAIN IF COVER FOR CIRCUIT BREAKER IS NOT PROPERLY SEALED.