IF YOU CANNOT FIND THE PROBLEM, BUY A "PRIORITY START UNIT" WHICH CONNECTS TO BATTERY & MONITORS DRAIN. WHEN BATTERY REACHES 11.9 VOLTS THE UNIT DISCONNECTS THE BATTERY. WHEN YOU ENTER CAR AAND TURN KEY, THE UNIT SENSES THE DRAW AND RECONNECTS BATTERY SO YOU CAN START AND DRIVE CAR. I WOULD BET ITS IN THE RADIO, THE ANTENNA MOTOR OR AMPLIFIER IF YOUR CAR HAS ONE. TRY TO DISCONNECT EACH PIECE AND THEN USE PROCESS OF ELIMINATION. I USE A DIGITAL VOLTMETER AND MONITOR CURRENT LEVEL AT BATTERY. MY PROBLEM CAME DOWN TO BEING THE RADIO RECEIVER IN TRUNK BUT I DONT THINK YOUR CAR IS SET UP THAT WAY.