I would not be surprized if the wiring/fuse order on yours is not the same as mine. The "red/green" only has power to it when the light switch is in either 'on' position. The "brown" (dark brown on mine) always has power. The "white" is switched on/off with the ignition switch. (on mine it looks like a white wire with a brown tracer because it seems to have a drip of somthing on it)
According to the chart in the owners handbook, the white wire sources power to the wipers, temp, fuel, heater etc, the brown is for horn, headlight flasher, hazard, etc the red/green is plate, parking, tail, marker and instrument lamps.
You should already have a white with pink tracer wire from the ignition switch for the stock radio. -I hope this helps.
Jerry