Hi I had the same problem with my 340. If u were sat in the car take the clocks out and the left plug will have a red and black wire . Check if that has 12v when u turn the ignition on . If it doesent then you have a brake in the system somewere I cudent find it so asked a freind and I ended up sold...

Ooo if this is still for sale when I get paid il have it of you