Mercedes-Benz S-Class
1998–2005

Illustrative — for orientation only.

Location

RHD (UK cars): driver's footwell on the right-hand side, tucked up under the lower dash trim directly above the pedals, within a hand's width of the bonnet release lever and just inboard of the foot-operated parking brake. LHD: mirrored to the left-hand footwell — forward of and slightly inboard from the parking brake pedal, alongside the bonnet release. The position is the same on every W220 body: short and long wheelbase, S280 through S65 AMG, with or without KEYLESS-GO. Do not go looking under the bonnet for a round 38-pin socket — the W220 dropped that arrangement and the 16-pin connector under the dash is the only diagnostic point on the car.

How to access

Small hinged plastic flap set into the lower dash trim, roughly the size and shape of the 16-pin plug itself. It hinges along its bottom edge with a small tab at the top — hook a fingernail under the tab and swing it downwards. No tools needed and the connector is visible the moment the flap drops. If the opening looks empty, the socket has almost always been pushed up behind the trim rather than gone missing; reach in above the aperture and pull it back down. If the tool won't power up, the socket is fed from the cockpit fuse box behind the trim panel on the passenger side of the dashboard, not from the engine-bay box.