http://www.all-forums.co.uk/forum/showthread.php?t=203253 go to this link this site will help you reset or find the cause.
I think if you find the bonnet cursor switch and press this a number of times the alarm goes into test stage. By opening each door this may give you the cause. Usually so i am told it is the bonnet switch which gives more plroblems than any other.
j corway, February 2007