A repetitive clicking noise from behind the center area of the dash panel is usually caused by a broken stepper motor actuating arm. The actuating arm controls the direction of air flow in the climate control system. Disassembly of the center console will be required to access and change the broken arm with the updated, reinforced part.
Car Problem Reports
Mercedes-Benz CLK55 AMG Broken Stepper Motor Actuating Arm May Cause Clicking Noise From Behind Dash
Mercedes-Benz CLK55 AMG Problem
Visitor, 2003 Mercedes-Benz CLK55 AMG, 117,000 mi
same issue as described above, I'm getting clicking noises from two areas. The front center dash and the driveside dash. I'm also not getting air on the driverside defrost