Two problems related to wiring have been reported for the 2009 Toyota Prius. The most recently reported issues are listed below.
Headlights go off without warning, sometimes left, sometimes right, sometimes both. Inconsistent and notice only at night. Can't fix and can't find solution. Headlights don't need to be replaced - there is something wrong with car wiring or other. I've had this car since 2009 and only had problem last six months or so - probably starting 1/2016. Car has approx. 65k miles on it. Very unsafe - especially at night in city when I can't follow another car and I can't tell if my headlights are on or not!.
The contact owns a 2009 Toyota Prius hybrid equipped with an aftermarket 10kw kit. The contact was driving 10 mph with the 10kw plugged in when it caught on fire causing the standard hybrid vehicle to become an electric vehicle. The electrical wiring caught on fire which was located in the rear passenger side of the vehicle near the tail light. The fire was extinguished by the contact and there were no injuries. The fire department was called but the fire had been extinguished by the time they arrived. A fire report was not filed and the vehicle was towed to a mechanic shop who was unable to repair the vehicle. An authorized dealer was then contacted and they stated that because the 10kw was an after market part, they would not provide any assistance. The manufacturer was contacted and offered no assistance. The failure mileage was 33,126.