I tried that too, I disconnected for an hour. No change. I also tried the security combination of lock and unlock with 1515 code. I can only imagine it has something to do with security considering it is killing the fuel pump and ignition circuit.

 

I ended up replacing my ECU and Alarm unit on my '99 D!. I got it from Goldwing Rovers, and then I sent the old units to Logan_gibson in AL, he reprogrammed it so the alarm system is disabled, and replaced the alarm unit. I guess it still needs to be there even if it isn't being used. been working ever since. Not sure if logan_gibson is still around but he was very helpful!!