Easy fix. Get a set of radio removal tools, these are also used to remove the climate control unit. Be careful to hold the climate buttons when removing the tools otherwise the buttons will pop off.

Once you pull the climate control, turn it over and look for a small square in a hole. Give this a 1/4 turn CCW and the bulb + holder will pop out. This is a one piece unit and the new bulb will come with the holder.

While you are in there, have a look at the climate control part number, if it starts with a 202 , this is the same unit as a ~ 96 to 00 C class ( mostly the 280 as the 220 / 230 had manual climate knobs ) To make it work on a SL, the version coding needs to be changed with a scan tool or some button pushes on the CC unit.