I have an '88 80 quattro and I don't believe the rear fog lights work. I have never seen them work So I don't know how it should look. With my lights on, I push the rear fog button and the light goes on. I go to the back of the car and don't notice any difference?? Does it just change the color of the light or something for fog, or should another light go on? If so, how do I fix it?