RepairPal Certified shops can diagnose and repair your 2000 Mercedes-Benz CLK430. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
It's possible it's the switch or motor. You need to check for power at the motor. If it has power then it's the motor. If it doesn't then you need to check power going to to the switch. The motors do go out on these though.
Alex