When you plug your player into the car, does it think that it's in the house? click here.

Hmm. If it did that, then you wouldn't need the restore DC/Car visuals would you. OK, so it's not that.

Do you have [output] notify=1 in your config.ini? Did Mark say that was required?

Do you have [serial] car_rate=115200 in your config.ini? There was some talk in another thread about how this might be required to get [output] notify=1 to work properly in the car.