W220 Seat Switch

the Mercedes-Benz S-Class (W220), the door-mounted power seat switch is actually a highly sophisticated Door Control Module (DCM). Instead of directly wiring to the motors, it transmits input signals as data frames across the interior CAN B network down to a separate main Seat Adjustment Control Module tucked underneath the seat cushion.Because of this interconnected design, troubleshooting a dead or erratic seat requires specific diagnostic routing.