Mercedes Vito W639 Rear Light Wiring Diagram -

| Symptom | Likely Cause | Fix | | :--- | :--- | :--- | | | Corroded ground (brown wire) | Clean ground point behind rear trim (left side) | | Fast blinking turn signal | Bulb failure or wrong LED bulb | Use standard P21W or CAN-bus LED | | Brake light stays on faintly | Water in connector or SAM failure | Dry connector, check for 12V backfeed | | No reverse light on one side | Broken wire in rubber bellows (tailgate hinge) | Inspect black/blue (pre) or white/blue (post) wire | | Rear fog light on wrong side | Bulb in right side housing (facelift) | Remove bulb – only left side is wired |