General information about on-board electrical equipment (Mercedes-Benz S-Class W220)

Cars of this brand are equipped with a 12 V electrical system with grounding on the negative pole. Power for all lighting devices and electrical units is provided by a lead-acid battery, recharged by an alternator.

This Chapter describes the maintenance and repair procedures for certain components of the on-board electrical system, which include, in addition to the specific ones discussed below, all lighting devices and electrical accessories not directly related to the engine. In addition, diagnostic procedures for general electrical faults are discussed. Information on the battery, alternator and starter is provided in Chapter Engine electrical equipment Manuals.

Attention! When performing any repair or maintenance work on components of the electrical system, it is imperative to first disconnect the ground cable from the battery to avoid electrical injury and/or fire.

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