i found out how to get the second rear foglight to work on the 9-5! on each side there are plastic holders that hold the reverse light bulb and the bulb for the reverse foglight and these plastic holders have metal wrapped all over them used as a conductor for the bulbs. and i noticed the one the side where the reverse foglight doesn't work, the metal is broken neatly where it travels over a small open square, and on the same spot where the bulb does work, this spot in the metal is perfectly intact.
this is a crude picture of the two pieces that i'm talking about. look at the middle of each piece there is a rectangular opening then to the upper left of each of those are a smaller rectangular opening but on the top on the metal is connected and the bottom one isn't connected.
i ended up just bending the broken metal piece down and then soldering it together, and now it works as well as the other side does
thanks for bringing up this post, or i probably never would have taken a closer look into this on my car.