As soon as I turn on the ignition, a clicking noise starts. It sounds like a vent opening and closing up under the front passenger's feet. It happens about 8 times over about 1 minute whether I start the engine or not. I can fiddle with all the climate control selectors but it makes no difference whatsoever. I spoke to the local MB Dealer and he said it was a vent actuator problem and the dashboard would have to come out and would be about 10 to 15 hours work to fix it!!! Help!