fog lights

Hi all, I have just bought a 2004 CLK 200 Kompressor. Love the car, such a great drive. One thing that I have noticed though and it really bugs me is that my left rear foglight comes on as soon as I switch the headlights on. If I swich the fog lights on, the left one stays on and the right...

My Tyres size is 235-45-17. But the spare tyre is 215-55-16. Is this normal? Or do I have a wrong size spare ?? Also does the 2.2cdi Avantgarde have 2 rear fog lights or 1 ?? The holder (and therefore bulb) is missing on rear nearside. I am told a car needs only offside rear fog light to...