Vauxhall Meriva petrol release cap sets off door alarm when car tries to lock doors new replacement fitted still sounds alarm

Trying to figure out the post . Is the car central locking working o.k ? Is it the petrol flap you think is triggering the alarm ,if so , how do you know it is this at fault ?

Central locking is OK..
Its when the car is trying to lock doors once you are driving ( anti highjack)

Alarm started AA called told it was petrol cap did something to the cap . replaced whole unit.
But fault still say a door is open.
When I lock the car all doors look including. Petrol cap.
Disconnected battery to see if it reset anything.

Hope this helps

After AA it was alright for 2 months.

There are a lot of possible faults that can trigger the alarm . The door locks have micro switches that often stick , spraying into the lock assembly with the likes of WD 40 often helps . Another cause can be damaged wiring in the rubber sheath where it passes through into the door frames . Add to that the bonnet alarm switch and also wiring which passes through into the top of the tailgate which again if damaged can be a fault . The movement of the car can cause damaged wiring or bonnet switch to make / break and set alarm off . Can be troublesome trying to isolate the cause for certain , unfortunately .