One problem related to turn signal has been reported for the 2010 Toyota Prius. The most recently reported issues are listed below.
I was leaving a parking space and exiting the parking area when both headlights went off leaving me in the dark. I pulled over and turned them on and off several times but nothing happened. I had the running lights, the turn signals, the high beams but no low beams. I drove home with my high beams on. I went today and replaced both bulbs then tried the lights again. Nothing. I took the bulbs back and exchanged them and still no headlights.