I understand this is fairly common problem for barchetta , so want to know what's the possible fix for this?
I recently changed the whole speedo unit to a new one because..you guessed it.. the speedometer stopped working

Now again for this new unit it has stopped working after some time.. along with the fuel gage , it comes/and goes away and sometimes works. but both the speedo and the fuel gauge stop/start working at the same time.. and when I'm actually low on fuel the Fuel light lights up so It does seems like there's just some bad connection somewhere probably on the whole unit which makes it go crazy.
Btw I do not want to buy a new unit again because seems like every barchetta has this problem and getting a replacement unit won't guarantee that it just won't stop working after some time.


Also anyone else have problem with their radio? Mine isn't able to catch any station, when it catches some its really weak and cripled signal , also the radio (when it finds any station) seems to work rather ok when you stand still, but as soon as you drive over 90km/h it pretty much isn't able to catch any signal or its super super super cripled.. It wasnt like this at start when I got the car, it has just got really worse in the past year.

Sounds like a bad connection to me. The act of disturbing the wiring to change the speedo could be enough to give a temporary repair. I don't know if there are edge connectors or multiway plugs but edge connectors can be temperamental. Try cleaning them with trichlorethene electrical contact cleaner.
As for the radio, you might have a faulty or damaged aerial cable / connection. Its quite a long way from the boot to dashboard. You could try another aerial connected temporary and just left loose or taped to passenger window.

There'a a thread on this here

https://www.fiatforum.com/barchetta/425437-barchetta-speedo-failure.html

There's no obvious quick fix though. Mine stops working when it's been parked in the sun - so it usually works OK in the UK

i just finished to repair mine with the same sinptoms described before , i followed the tip off Ilkka on the other thread and i found 4 soldering joints with tiny craks , exactly the ones that conect the speedometer nedle actuator to the eletronic board , i resolder it , put all together and ... sucess
i have drive it for some 100 km never failed again and seems more smooth