[simonclay]

If you are sitting in the car looking at the hole in the dash where the radio was, on the left side there is a metal brace that runs vertically. Look to the left of that and you should see a black bundle, if not stick your hand in there and feel for it. When you get it pulled over and are able to work on it, pull the black covering off of it. You should see half a dozen or so wires. Sort through and find the brown one, and there you go.

Be careful though, there isn't much slack on the ignition wires. So don't go cutting too much sh*t up, lol

And yes the orange and yellow should be hooked together, even though it wouldnt turn on. Those wires provide constant power and that is how the head unit saves settings and such. It's the red "switched power" wire that actually makes the head unit turn on and make beautiful music lol.