Warning light keeps flashing after locked, and fuse #5

Hi,

Sometimes, after locking the car with pressing Lock on the key fob, the orange lights flash three times (as it should), then keeps flashing very fast, and the interior lights stay on, as if the alarm just set off and no siren sound.

I found that, if I pull the fuse #5 in the fuse box that's located in the back of the trunk, it will disable it from happening. However, the red light on the truck button inside the car stays on, and no flashing three times at all when locking. It just locks the car.

I did a few research, it seems the problem is the battery inside the siren need replacing. Where is it located on a Right-Hand-Drive (UK/Japan specs) car? Do I need to replace the whole siren or I can just replace the battery?

Also, if I leave fuse #5 pulled, will it drain the car battery with the red light stays on all the time? And any other side effects?


Thanks