If one or more of the switch lights on your center dash console are not working here are the bulbs you will need to fix the problem. ( Note if ALL switch lights are not working it could also be a bad dimmer switch - poteniometer). The clear bulb is used at the center hub of your optic lights going to the upper switches. The frosted bulbs are used in the climate control panel to prevent being too bright at night. The clear bulbs can also be used in the warning lights on the instrument cluster. Getting to the holders behind your wood pieces to replace the bulbs can be difficult if you are not familiar with the proper replacement procedures.
Kent has produced free video instructions on how to get to these bulbs on the 123 and 126 chassis 240D, 300D, 300CD, 300TD, 380SEL, 300SD 300SDL, 500SEL, etc.
Mercedes 126 Chassis Switch Panel Removal and Dash Light Repair by Kent Bergsma
123 Chassis Center Console Wood and Switch Removal by Kent Bergsma