Modern Vespa

I changed both bulbs even when the old ones looked fine but did not fix problem. Right turn indicators are working fine. I read in an old post that if one side is working then the relay is working so im kind of baffled as to whats going on. Any clues?

Thanks in advance.

If one side works normally and the other doesn't, it's the switch.

Are the rear bulbs working

I changed both bulbs (even though the old ones looked fine)

So that's a no, then?

Just replace the switch...