[IainG]

Hi
Have a look at the metal conductive track on the housing that holds all the bulbs on the side that isn't working. Check the track is intact, and not cut. You could then just touch on a live wire on the track to prove the bulb actually works.
Easy way to check for correct wire is with a meter. Switch on the fog light and find the live wire or wires at the rear light cluster then switch off the fog light and see which voltage disappears, recheck and then loop that over to the other side, touch it on whilst live at test that way, when proved just connect up. Think the pins come out, you have to push a thin sleeve down the terminal to release a spring tang to pull the pin out.