Volvo Repair: Battery Losing Charge, diode bridge, negative cable

Question
Latley my battery has been losing it's charge when left to sit overnight. I've tried connecting a test light betwwen the disconnect negative cable and negative post. I've pulled all the fuses and it still shows continuity! What's up?  

Answer
That means the circuit that is draining the battery is not controlled by fuse. My guess would be the alternator, try disconnecting the positive bat wire off the alternator. If this fixes it, that means the diode bridge inside is probably shorted, which means alternator replacement.