I have a 2000 clk430 convertible.
Tonight the fog lights... the green dot by the switch would not go out.
Removing the key and locking the car with all the doors shut did not result in them going out for over 2 hours...
Vigorous working of the switch in and out as well as off and on did nothing to fix the problem.... even opening the hood and whacking the electric box on the passengers side did nothing...

removing the battery did work and the lights stayed off after re attachment.... however they still latched in upon reuse of the fog lights...

when disconnecting the battery a second time a heard a relay click in the electrical box as it was disconnected.

Any ideas which relay is bad....? or is it the circuit latching it in that I need to find?

I also confirmed that the door switches were working properly by pressing them and seeing the window actuate.

Thomas