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 C240 Broken Stepper Motor Actuating Arm May Cause Clicking Noise From Behind Dash
Mercedes-Benz C240 Problem
Average Mileage: 104,424 mi (27,000 mi - 255,783 mi)
Visitor, 2003 Mercedes-Benz C240, 76,000 mi
clicking noise under the center of the dash upon starting the vehicle. Heater only blows at the windshield and never anywhere else no matter how I set the air flow controls.
Visitor, 2003 Mercedes-Benz C240, 140,000 mi
recently began - hear the "clicking noise" upon startup for about 60 secs - seems to be from the AC/Heater so I turn it off and on. while the noise is "clicking" air flow is greatly impared. Not liking what I read here as sounds like it is going to be yet another expensive repair from what I though was a High Quality Automobile - Mecedes - NOT! just a very expensive automobile to maintain and OFTEN! very disappointed!
Visitor, 2002 Mercedes-Benz C240, 27,000 mi
Clicking sound behind the dash. Clicks 8-9 times then stops. Dealer diagnosed as a $439 repair.
So, is it okay to drive the car if the Stepper Motor Actuating Arm is broken? I certainly would not want to further damamge the car. Just want to know how much time I have to get my monies together.
Visitor, 2004 Mercedes-Benz C240, 74,000 mi
Price of $1200.00 to fix and this prices not from the dealer.
Visitor, 2001 Mercedes-Benz C240, 60,000 mi
broken stepper motor actuating arm
Visitor, 2002 Mercedes-Benz C240, 168,000 mi
same clicking noise behind dashboard
Visitor, 2004 Mercedes-Benz C240, 60,000 mi
As described by others, clicking noise heard when turning on Heat / AC. Sounds like flappers moving in vents as air flow changes between outlets. Usually stops after a few minutes. Quita annoying.
Visitor, 2002 Mercedes-Benz C240, 255,783 mi
I have the exact same problem. At every start there is a ticking sound coming from behind the air vent and last for few minutes. Air conditioning has been effected since then.
Visitor, 2003 Mercedes-Benz C240, 156,000 mi
clicking behind dash from control unit for HVAC vent.