2009 Ford fiesta ztec s and my car alarm keeps going off!

[Charlie muir]

Hi I have recently brought a 2009 Ford fiesta ztec s and my car alarm keeps off in day light. It can starts at about 5 in morning and go off randomly in the day. But doesn't seem to go off at night when it's dark. It was fine for the first few days but then it started. Does anyone know what the problem is and how to solve it.

Thanks in advance charlie