I would always suggest the use of a test meter. Even with a cheap multimeter (http://www.maplin.co.uk/Module.aspx?...37279&doy=15m2
) at £5.99, and a little experience, you will be able to identify +12, +12V with ignition, +12V accessory etc.
Sorry, I can't help with the colours, but even if I think I know the colours, I would always test first. It could save a blown fuse, a flat battery or worse.