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 C320 Broken Stepper Motor Actuating Arm May Cause Clicking Noise From Behind Dash
Mercedes-Benz C320 Problem
Average Mileage: 101,971 mi (27,503 mi - 205,000 mi)
Visitor, 2002 Mercedes-Benz C320, 123,000 mi
clicking when you start car. then stops after 3-4 min. sound comes from top of dash board
Visitor, 2001 Mercedes-Benz C320, 100,000 mi
Clicking noise for about three minutes before stopping. Every time you start the car.
Clicking repeating noise coming from inside the dashboard. Not all the time but I have heard this quite enough...
Visitor, 2005 Mercedes-Benz C320, 69,500 mi
Every time the car starts I hear a clicking coming from behind the dashboard. It clicks for about 1 minute and then stops. I don't hear it again until the car is started again. If I start the car and then turn it off the clicking continues for about a minute and then stops.
Visitor, 2001 Mercedes-Benz C320, 103,000 mi
CLICKING NOISE FROM BHIND OF DASH . STOPS WHEN I TURN ON HEATER FAN
Visitor, 2001 Mercedes-Benz C320, 128,000 mi
This has happened twice, first time covered by warranty,now doing it again, too expensive to fix.
Visitor, 2004 Mercedes-Benz C320, 78,000 mi
Clicking noise behind dash board.
Visitor, 2001 Mercedes-Benz C320, 95,000 mi
Once I start the car, I hear a clicking noise from the behind the dash. When it started it was only about 45 seconds, now it is going on for about 1 1/2 minutes to 3 minutes. Now I hear at least two motors clicking. It affects the AC and the Heater function, to the point that the AC will run by itself when turned off, Half my windshield will not defrost (Passenger side) and I believe it has affect the entire AC system.
Visitor, 2001 Mercedes-Benz C320, 117,000 mi
Gotta take out the dash and replace a few motors and plastic clips. 6-10 hours depending on ability and tools
Visitor, 2003 Mercedes-Benz C320, 65,000 mi
Clicking noise for about 8 times every time I start the car