Who to know which sensor is faulty in alarm system?

[wawa]

Hello

Thanks ppbon for the tips. I've check:
the door, ok
The rear trunk, ok
the front trunk Light not always coming on but most of the time. ok
then check the ood compartment (between both seat for rdougan) and voila!
The odd compartment hinge have been change and it does not close correctly. When I manualy push down the little switch, the alarm set on ok. So I modifie it a little bit for now so the alarm is ok.

So now I need to find a picture for the hinge of the odd compartment so I can repair it as original.

Thanks
for the tip on how to find it out.

wawa