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.Google+
Car Problem Reports
Mercedes-Benz C230 Broken Stepper Motor Actuating Arm May Cause Clicking Noise From Behind Dash
Mercedes-Benz C230 Problem
Average Mileage: 74,172 mi (40,000 mi - 145,000 mi)
Visitor, 2003 Mercedes-Benz C230
CLickin noise from dash for about 8 repatative clicks the it guits. AC diverter control does not work.
The clikcing is more like the sound of the keys but I know it is coming from the dashboard area.
Visitor, 2002 Mercedes-Benz C230, 145,000 mi
clicking in dash
Stepper motor making noise. Because the front panel has to be removed to fix it, repairs are costly.