1999 996 Cab Fuse C3 (door lock) blown car won't start

[ckroeger]

Hi,
1999 Porsche 911 (996) Cab - Automatic Trans., Aftermarket Alpine Radio
I'm trying to track down a bad alarm switch (I think). Following are the symptoms:
1. Alarm double beep when activating
2. Door Locks and Windows don't work (15 AMP Fuse C3 blown)
3. Battery is fully Charged
4. I disconnected the ignition switch, reconnected the battery and fuse still blows
5. I disconnected the door lock switch and fuse still blows
6. I disconnected the overhead light array and the fuse still blows
7. Car (basically) does not start (fuel pump works). Car will start intermittently, but maybe 10% of the time trying
8. I replaced the ignition relay (old one was working but showing some resistance on the ohm meter)
9. Problem surfaced when I stopped for gas, filled the tank and the car wouldn't start. I realize there's a lock on the gas cover...have not done troubleshooting on it as I think I have to remove the wheel well to get to it.
10. If I had a wiring diagram, it would make things a whole lot easier!!!
11. I connected a scanner...no faults...I got a green light...however, the scanner does not check the alarm codes
Any help would be appreciated.
Thank you