Specific wiring harness for retrofitting halogen headlights to xenon headlights code 615/621/622 for Mercedes M-Class W166 High-quality adaptation in original equipment manufacturer quality Only one set is required to connect both headlights The wiring harness connects the headlights to the central electrical system as well as to the sensors for the automatic headlight range adjustment (only for vehicles without Airmatic) Selectable option: Without Airmatic air suspension (code 489) With Airmatic air suspension (code 489) Scope of delivery: Wiring harness Note: When retrofitting the intelligent lighting system ILS code 622, the headlight range adjustment control unit A166 900 29 06 is also required