Is there some way to operate the radio once the hybrid system is turned off? If so, does it operate off the main battery or the 12V battery?
Push the power button once (accessory mode) or twice (IgOn) without pressing the brake pedal and you can operate the radio off of the 12v battery.
One warning though... don't do this for too long. At least with my '01, I sucked the 12v dry in less tha half an hour, using it to play the radio while camping with some friends. I thought I had left the car turned on, but apparently left it in the accessories mode. That little 12v doesn't last too long if you use it for more than just cranking up the computer and turning the main batteries on.
