What causing an airbag malfunction in my Mercedes-Benz CLK 350 and does it mean the airbags aren't functional?

I have been having problems with the airbag warning light since last September on my 50,000 mile 2006 Mercedes-Benz CLK 350. The light has been on for the majority of the time and four repairs have so far been attempted. One question that I cannot get a straight answer to is whether, if the light is on, I have functioning airbags. The local non-franchised garage says no, but the dealership is not forthcoming with an answer.

I do have an extended warranty so the cost is not an issue, but the inconvenience of the dealer having the car for a day to diagnose the problem, and a follow-up to fit the new part once it has arrived, has become too much. The last repair was yesterday and the warning light appeared this morning. They now want the car for a week but after four attempts I cannot see that this is going to be of any benefit. How should I proceed?

Asked on 2 May 2011 by SB, Arundel

Answered by Honest John
These are often triggered by speed humps, especially if the car is on bling 19-inch wheels with 35-profile tyres at the back. There is not enough tyre between rim and road to cushion the shock so they set off the airbag triggers.
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Much better second attempt at CLK. Goes well, handles well and is comfortable. Attractive looks.