If you haven't already made the connection. I would recommend connecting on the Brake Light side of the connector as it's cheaper to replace than replacing the Loom.
As I recall the brake light is Red and earth/ground is Black.
For future reference the colours from the connector to the rear cluster are:
Ground = Black
Brake Lights = Red
Tail Lights = White
Right Indicator = Grey
Left Indicator = Blue
Licence Plate Light Live = Black/Brown
Licence Plate Light Ground = Green