A friend tried to open the 3rd passenger (not the one behind the driver) back door from inside but the latch/spring mechanism seems to have broken. It does not lend the typical resistance every other latch does at the moment the door open it just springs back and forward without doing anything. However central locking still works and the door can be opened from the outside. What sort of repair am I looking for? Would this be covered under warranty? Thanks for your help
Have you checked that little switch on the door that you can only see when the door is open? The one that disables the back door latches so your kids can't open the doors at highway speeds. If it flipped somehow accidentally, it would feel like that. See the owners manual about child safe doors if you don't know what I'm talking about.
Oh... and if that is the problem, I'm sure your warranty would cover somebody flipping the switch....