Hi Ken,
I've recently replaced the flasher relay in my SLK's CCM/Multifunction Module as the contacts had stuck closed. It's not an easy job though - one person to heat the relay with a hot air solder station and another person to heat the pins on the other side of the circuit board with a 80W wide tipped soldering iron. It's easy to damage the printed circuit board. The relay seems to be a common failure. If there is enough demand I may be able to supply new relays or provide a relay replacement service.
Regards,
Tony