Factory head units are called out as a common pain point, with many cars carrying hacked-in aftermarket radios and butchered wiring. The preferred path is to send the original Becker unit to a specialist (Becker Autosound / Becker Sound in NJ) for rebuild and optional Bluetooth, keeping the dash factory-looking while adding modern connectivity.
Original stereos and Becker radio refurbishment
Mercedes-Benz S-Class (W126) · ownership