it's a lot simpler than that, hopefully. On some Mercedes ignition locks, there is a key way in the electrical switch that prevents that connector from being removed unless the key is turned to the first position, the same position to remove the steel theft deterrent collar. Move the key left / right of position one if the connector still won't come out. It is a pretty narrow window.

Note: The elec switch is held with 3 slotted screws so make sure you have the correct bit. It may be less frustrating to replace them with socket head screws for easier installation.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked