Hello, i have a 2002 mercedes c class coupe. The front lights are always on! I think they are set to be on as per the european driving rules - how do i turn them off? thank you.

You can disable the day time running light system by removing the DRL relay or DRL fuse. In fords for example, it's a simple relay in the fuse box.. with Mazda, it's an actual DRL computer unit inside the dash. On some vehicles you cannot disable the DRL and you will require a DRL relay harness. Some harnesses are polarity sensitive and you could fry the electronics if you're not careful. Also on some cars, by disabling the DRL, you will trigger the onboard computer to detect a fault and trigger your check engine light or battery light

The headlamp switch in your Mercedes is not a ‘traditional’ switch. It works on digital signals that are sent via a CAN bus to a control unit.
You have OFF, Auto, SIDES, ON.
If you can not turn the lights off when the switch is in the OFF position, then either the switch unit is faulty, or the CAN Bus/SAM have a fault.
You need a dealer or Independent Mercedes specialist with a STAR machine (no other diagnostics machine is useful for anything other then engine fault codes) to read the units in the car to see if one is faulty.
Why not join the Mercedesclub.org.uk, its free and I’m sure they will have seen this fault before.
If you have already solved this fault, please post back and let us know what you found.
Thank you.