I bought my wife a fiat 500 on a 2012 plate in august/september 2021 from a dealer in weston-super-mare and for a 2012 plate
its in white and immaculate condition both inside & out . we had the same issue with the rear numberplate bulbs that stopped
working not long after we bought it, so it went back to the dealer where it was bought under their warranty . They were supposed
to have sorted it . we got the car back and not long after that, the bulbs stopped working again . I was recommended by a colleague
where I work, to take the car to a company in highbridge ( profix ) for them to investigate and fix . They found the garage where we
had bought it, had made a complete mess of it . It was so bad they took pictures and posted them on facebook .
Suffice to say we needed a new loom to the boot electrics........job done . Its more than likely to be the loom . However, not long
after that the bulbs stopped working again and I fitted 2 new bulbs which again sorted the problem . They recently stopped
working again . I was going to fit 2 new bulbs again but have found that where the bulbs slot in, the metal connectors just need
pulling in a bit so the bulbs are tighter, just one and both started working again . so when the car goes in for mot again, I'me
gonna get some new bulb holders fitted . A new or replacement loom ( top left when you open the boot ) is not an expensive
fix . hope this helps .