hello - 1991 200tdi disco - after the battery going faulty and upsetting the alarm which was fitted when the car was first bought the alarm will not work at all. It is a very old - 1991 - scorpion alarm. Before the red indicator used to glow when the alarm was operative but doesn't now. The central locking works ok on the key. Has anyone any info on these alarms please - a spare working unit or wiring and circuit layout - ta for any help