Pretty simple on this version of 126. Remove the radio by removing the ash tray then remove the 2 screws holding it's frame in. Once you get radio out by pulling down on the 2 clips at the bottom of the radio, look up at the bottom of the wood and you will see 2 more screws, remove these too. Now gently pull out on the bottom of the wood and tada there are the bulbs sticking in on the back side of the push buttons. Gently tug/twist/wiggle on the bulb holders to remove them from the buttons. Replace all 4 of them while you are there. Warning #1! Some of the bulbs may have melted the buttons so getting them out will be a fight. Just work carefully and you should be ok. Be real careful of the wood!!! Warning #2! DO NOT disconnect the radio power wires! If you do and your car is a 1986,1987 or 1988 you will be making a trip to your local Mercedes dealer to have them reset the radio. All other years need a code so make sure you have it. This is not promise that the radio will not go into theft mode.