Hi, it started on Saturday, when I start the engine the back wiper starts, even thought is in the "off" position. I have to turn it on then back off but it doesn't go back to the start position, I will just stop wherever. any ideas?

Check the wiring leading through the rubber tube to the boot lid you probably have a broken wire or two

Yup, search 'boot wiring', buy the kit and fit.

D

You are not alone.....

https://www.fiatforum.com/500/471804-fiat-500-tailgate-wiring-fixed.html
https://www.fiatforum.com/500/455490-top-rear-brake-light-not-working-wiring.html

Paul m.