Security system problems

[towanda]

My alarm system triggers almost everytime it is set. The lights do their little dance routine and I occasionally hear a faint squeaky alarm. My local dealer diagnosed the problem was with a movement sensor. According to my owners manual, I don't have that option because I don't have a button to disable it. Is there some other movement sensor that can cause this issue? I spoke with a different mechanic who seemed to indicate the movement sensor was tripping the alarm and it wasn't the optional one. The silent or weak alarm is a second problem that he thinks is unrelated to the tripping. Any ideas? If there is a movement sensor causing this, where is it located?
Thanks.

[towanda]

Sorry, forgot to mention, this is on a 2004 xc70.