Rear Fog Lamp

Having a look into the rear tail gate inner guts yesterday I found looms going to the red inner lamp panels on the tail gate, my idea is to have a rear fog lamp in the o/s lamp panel, there is a 3 wire loom to another loom/buld holder but as mine had a tow bar its gone umpteen bits of extra wires and cut off pieces too, I checked and have 12v power to a green wire which when the lights are turned on is powered, turn off lights power stops, turning the fog lamp switch on the stalk doesn't change anything. So my idea is to some how use that feed at the rear to link into the fog light switch on the stalk so both front and rear fogs will come on

Make sense? anyone else done this?