Hi,
first check in the boot under the foam plastic to make sure its not like a swimming pool. If that checks out OK then its the alarm siren causing the problem.
Does the alarm go silent when you pull the fuse?? if so it means the internal battery for the alarm sounder has failed, its probably leaked over the circuit board causing the false alarms.
As a stop gap you can disconnect the alarm sounder ( instead of pulling the fuse) as that way you can still lock the vehicle and set the alarm but it wont make a sound.
The alarm siren itself is under the lower windscreen trim where the wipers come through. its just on the passenger side!
There is quite a few threads about removing it and also possibly replacing the battery. My alarm started doing the exact same thing 4 weeks after buying it, it spent a week with the alarm disconnected without problems and after replacing the internal batteries its been fault free for the last 12 months.
found one of the threads
https://www.crossfireforum.org/forum...d.php?p=770974
Matt