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Diagnosis and Repair of the SAM Unit in a Mercedes C-Class

Model: Mercedes Classe C W205 - Years 2014-2021
Part: Checks and maintenance

Symptoms indicating a faulty SAM unit: turn signals, windshield wipers, and power windows not working; instrument cluster off, along with the heating system. The SAM unit is essentially an intelligent electrical control center: you give a command, and it transforms it into an action. The YouTuber cleaned the printed circuit board of the original SAM unit, but this only led to partial success, as the power windows and turn signals remained off. Therefore, it became necessary to replace the SAM. It is essential to find a SAM unit with the same component code, as this indicates which vehicle it can be installed on, the physical shape it must have, which fuse or relay protects it, its firmware, and the functions configured within it. Once installed and all functions tested, no programming was necessary because the part number was identical. Several warning lights then appeared on the dashboard because some connectors had been disconnected: the errors must be cleared with a scanner.

Posted on 18 April 2026 by ScegliAuto

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