Ive found a perfect retained accessory power source within the power window system. the power windows require a heavy gauge power source to operate the motors, which can be found at the drivers side window switches. the front switch will have a heavy gauge power lead, and behind it is a slightly smaller gauge wire. with a test light, check the large one for power once the ignition has been on, with the door shut. open the door, and if the light goes out, youve got your man.
tapping this power source will allow you to power your aftermarket stereo or any other aftermarket accessories for up to ten minutes after the ignition has been turned off, but will turn off as soon as you open the door.
as well, if youre brave, confident, and dont care too much about preserving your stock HU, you can dissassemble it, leaving only the motherboard and ribbon for volume and power control (the brown wires from the volume control board will have to be cut, they lead to the bass and treble controls, which cant be removed from the faceplate as the knobs are glued on, however, they are all in order starting from a brown/black stripe wire on one end, and can be reconnected if for some reason you must reinstall your stock HU) this allows you to conceal your HU in a much smaller space, wrapped in some insulation, without having to relocate it or remove anything important from inside your console to make space for it. with the volume/power control still attached, the deck will never automatically turn on in the case of a disconnected/reconnected battery, leading to radio noise if youve somehow tied your aftermarket HU into the bose speakers.
i havent tried yet, but to preserve the stock chime sounds, i will attempt to piggyback the bose speaker leads in the doors with my aftermarket leads onto my aftermarket speakers, allowing the chime to be broadcast through my aftermarket system. im a little apprehensive, as this may cause feedback or distortion, maybe damage even though my stock HU is turned off.