I have been checking on this problem, there appears a couple of possibles :
The main car battery is getting ole and does hold its chrge well (the battery voltage dops back after running and the alrm see this as a tamper attempt and sounds the alarm.
The small rechargable batteries in the power sounder (mounted behind the wheel arch liner) can die of old age - the fix is replace the power sounder or if you feel upto it you can open up the power sounder and chnage the batteries
The bonnet switch (rear right of engine bay (viewed from front) especially on dark coloured cars due to heat expansion of bonnet
Timbo, July 2009
