Found this on the net a while back don't know if its of any use?
300TDI Discovery Stereo Wiring
wire colour chart:
B=BLACK.
P=PURPLE.
G=GREEN.
R=RED.
K=PINK.
S=GREY,
L=LIGHT.
U=BLUE.
N=BROWN.
W=WHITE.
O=ORANGE.
Y=YELLOW
L denotes lighter colour i.e. LG indicates light green as opposed to G = green being a darker colour.
Left front speaker +(positive) BW = black with White tracer
Left front speaker - (negative)BN = black with Brown tracer
Right front speaker +(positive) BK = Black with PINK tracer
Right front speaker - (negative)BR = Black with Red tracer
Left rear speaker + (positive) BY = Black with Yellow tracer
Left rear speaker - (negative)BO =Black with Orange tracer
Right rear speaker +(positive) BG = Black withGreen tracer Right rear speaker -(Negative) BU = Black with Blue tracer
SUB was originally in its own connector two wires RED and BLACK with a shield around it and black sheath over outside.
I connected mine to a phono jack plug and plugged into an amp out socket on the back of my head unit
Red to centre pin
BLACK to the outer you need to ground the shield to the head unit casing.
Sub is powered by its own amp which is built in to the tailgate and is powered from the ignition circuit so will switch on and off with the key at the first stage.
You can test the speakers by touching the relevent pos and neg wire to a little 9 volt battery the speaker will make a pop sound lets you know the wires you have are going to the speaker you want.
