Focus Mk1 Central Locking

[Paddyman]

Hello, I'm a new member and would appreciate some help. I bought a 02 focus estate a few months back to use for work, but after using the car for a few weeks I've decided it's too good to use for work (painting and decorating) and give it to the wife.

The problem is the previous owner had the passenger door replaced after a bump, so the central locking is not working as it should.

The central locking only works with the passenger door lock pressed in and it does not unlock with the rest of the doors when I press unlock.

When the passenger lock is in the unlock position the central locking motors will lock, but then unlock straight away.

Before I spend any more time and money getting this sorted, are there any obvious solutions I can try first as the motors all appear to be working.