Rear light cluster wiring uses

Right hand light cluster:
Grey / Yellow - Tail lights feed (goes to two lamps)
Brown - Negative
Blue / Red - Stop / Brake Light Feed (this loops out to the left hand light)
Blue / Yellow - Reverse
Blue / Brown - Indicator Feed

Left hand light cluster:
Grey / Violet - Tail lights feed (goes to two lamps)
Brown - Negative
Blue / Red - Stop / Brake Light Feed
Blue / Yellow - Reverse
Blue / Brown - Indicator Feed