The SAM module controls the lights electronically. Unlike older cars, the W639 does not have traditional fuses for each rear light; instead, the SAM unit provides overload protection. If a light fails, check the SAM unit’s diagnostics first.
In most markets, only the driver’s side rear fog light is active. The passenger side pin is often unpopulated. If you want twin rear fogs, you must run a wire from Pin 5 of the driver side to the passenger side. mercedes vito w639 rear light wiring diagram
Pre-Facelift (6-pin rectangular) -------------------------------- [ Pin 6 - Fog ] [ Pin 5 - Reverse ] [ Pin 4 - Turn ] [ Pin 3 - Brake ] [ Pin 2 - Tail ] [ Pin 1 - Ground ] The SAM module controls the lights electronically
After checking the bulbs and finding only a "black tinge" on one filament—a classic sign of arcing—Marcus dug deeper into the . He discovered an oily substance on the 20-pin inner connector. Once cleaned, the resistance stabilized. The "ghost" in the machine was gone, and the Vito’s lights shone clear and steady once more. Key Components for Repairs In most markets, only the driver’s side rear
Have an assistant turn on the desired function (e.g., the indicator). Probe the pins until you see a pulsing 12V signal.
The W639 features distinct rear light clusters depending on the body style (Panel Van, Dualiner, or Traveliner), but the core lighting functions remain consistent. Each cluster typically houses: