Hi guys, this is as much for me as it is for you so I have a record of it on my thread, but if you need a bit of assistance with the wiring in the Z3 harness at the rear of the car "pre the rear light assy plugs" then here we go.
Lights L/H rear
Brown - Negative
Blue/Green - L/H Indicator
Blue/Yellow (2 wires) - L/H reverse (and feed for R/H Reverse light)
Yellow/White - L/H Fog light
Grey/Violet - L/H Tail light
Blue/Red - L/H Brake Light
Lights R/H Rear
Brown - Negative
Blue/Yellow - R/H reverse light
Blue Red - (2 Wires/Diff Gauges) - R/H Brake Light (and feed for L/H Brake light)
Yellow/White - R/H Fog light
Grey/Yellow - R/H Tail light
Blue/Brown - R/H Indicator
Hope this helps if needed. Cheers