This is a linkage problem inside the door either from the lock to the mechanism itself or the lock itself.
Fiat punto door lock problems.
Quick repair on a 2006 fiat punto grande that both back doors will not open from the outside useing a cable tie.
Many owners of fiat linea and punto are facing door locking issues is that door can be open from inside and could not open from out side.
I have try to overcome this issue.
In this video i have try.
It will be obvious you will see a disconnected or bent linkage when you look at it.
Punto s central locking failed within a day of fixing ac relay problem i felt happy and thought i will have a trouble free run after i changed ac relay.
But you will see what the problem is as soon as you get inside the door.
Persisting problem with fiat punto door lock the zen i used to have had problems with a rear door lock.
See post no 7 in the following thread for the location and colour of the wires that you need to connect.
All you need to do is connect the output wires for indicators to the two indicator wires in the wiring loom.
There is one wire for each side of the car.