Make sure to disconnect the battery before removing the airbag, and keep the battery disconnected the entire time. When I replaced the combo switch on my W210, I made the mistake of reconnecting the battery without the airbag connected (to telescope the steering wheel outwards). The SRS light became activated, and I had to go to an indy to get it turned off at the cost of 1 hour labor. Only dealers or SDS-equipped indies can reset this light, as a regular code scanner won't do it.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280