IIRC the DIY I saw just had a wire strung from the back of the working one to the back of the idle one.

 

I removed the right tail light during my LED update and found a bulb and socket for a right side rear fog. I'm assuming it's for the RHD vehicles but does anyone know how to activate it?

 

I tried to get access to the actual wiring harness connector that provides power to the right rear "fog" light. My plan was to tap the powered wire at the connector carrying the voltage, and splice it into the other rear fog light wire at the connector. The car is actually wired with wiring to both tail fog lights. However, depending on the country the car is intended for, only one rear fog will actually be wired beyond a certain connector. That connector as far as I can tell is buried inside the right side of the car along the passenger door jamb. Long story short, I finally gave up when I figured out I'd have to take half the inside of the car apart to get to the connector.

My alternate solution is simple and reversible, but not as elegant. I simply did as some others have suggested and ran a wire from the lead from one rear fog light to the other. I can't remember which wire it is, but it's pretty easy to find by removing the tail light from the car, pulling the fog light bulb assembly out of the tail light, and taking a close look at the wiring going to that specific bulb connector. I tapped into the fog light wire with a cheap (but removable) crimp type connector made to tap into the wire (without having to cut it) the other end of which is a male blade connector. I picked these up at Radio Shack, but many automotive or trailer stores will carry them. I also connected one to the other (unlit) tail fog light wire. I then used a piece of wire of slightly larger gauge than that used in the tail light wiring harness long enough to run between the tail lights, and crimped female blade connectors to each end of that wire. If you remove the strip of horizontal trim that sits just under the engine compartment lid (held on with phillips head screws), you can hide the wire under it and you won't be able to see it. However, be careful not to run it directly under the trim as you will crush it when you reinstall the trim piece. Plug in the jumper to the connectors you hooked up to the tail fog light wiring and your done after a little more minor reassembly. If you use the blade type connectors, you and easily remove the "jumper" in order that your tail lights not actually be wired together. And of course, with the crimp style "power tap" connector, you can easily remove all traces of your handy work if desired.