1. disconnect the negative battery terminal
2. disconnect the RED SRS plug under the passenger footwell/carpet
3. Unscrew the airbag 2 torx screws behind the steering wheel (T30 maybe?)
4. Remove the airbag, unplug the connections
5. Remove the steering wheel - 1 10mm hex key (if the steering wheel has already been removed this will be much eaiser - you may need two people)
--NOTE: Do not use the steering lock as a counter brace, have someone else hold the wheel.
6. with the wheel removed it will be pretty easy to get the combo switch out, there are a few screws to remove and it should come out. You may have to remove the steering angle sensor - I don't remember.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE