The central locking on my 2015 500x will not lock the doors either with the fob or when pressing the driver's door internal lock. When the fob is pressed you can hear a faint click at each of the doors but the locks don't operate. I've checked Fuse 38 and it's ok. The boot lock still works. The car has the keyless entry system and the local Fiat garage has just replaced the driver's door handle as they said there was an error code showing this was faulty, but it hasn't solved the problem. Any ideas?