An expensive problem with a three year old Fiat 500 is the failure of the wiring loom where it passes through the rear of the body into the tailgate via a convoluted rubber gaitor. The central locking will fail and you can no longer open the tailgate(except from the inside via the emergency lever), various warning lights come up on the dashboard etc.The loom is subject to bending stress here every time the tailgate is opened and shut. The more it is used the earlier the wiring will fracture and break, for instance, daily use for shopping or letting a dog in and out. The main dealer solution to this car was a £600 fit of a new wiring loom. However, with a little patience there is a simple repair that costs about a £1. First, pull some loom through the gaitor from the C pillar., then remove the internal tailgate pressed board cover to reveal the wiring connections, disconnect the two rear heated window connections, the rearwiper motor connection and undo the rear lock which allow you to pull some loom through from the tailgate. Now you can see the broken connections. Carefully strip each broken wire, slide on a heat shrink sleeve and twist the bare ends together. Solder the wire and when all the broken wires are repaired this way apply some heat to shrink all the sleeving down to a tight fit. Relocate the convoluted rubber gaitor and finally carefully pull all your new wiring connections through into the tailgate, connect up the rear screen demister etc and refit the pressed board cover....Hey presto you have saved about £600 !