Mary ..... there are numerous things that can cause this. I had a Galaxy, which is a rebadged Sharan, but never had problems with the alarm. What you can do is to register on this site and ask the same question as the people on there are very experienced and will have a solution to your problem. I saved £100's using this site;http://www.fordgalaxy.org.uk/ford/index.php?act=idx
Chris
February 2008