If you need +12V when car is ONLY in reverse for your aftermarket radio/camera, this is where you can tap into it on a 2005 Gen2 in the front kickpanel. (likely the same on other G2's) Red wire in drivers kick panel area.
2005 never had backup camera from the factory so I don't think there's a wire behind the MFD like 2006-2009 would have.