Mercedes-Benz Wiring Diagram Resources: Official Factory Schematics, Fuse Box Charts and Electrical Troubleshooting Tools

Last updated: October 27, 2026

This page collects the places to find Mercedes-Benz wiring diagrams and schematics, plus the fuse box charts and tools you need to use them. Bookmark this page as it contains invaluable resources. Our goal is to keep the resources on this page updated at all times. If you know of any website that we should add to this list, please send us an email. Note that we do not endorse any outside website. You will be leaving the Mercedes Medic website and being taken to the resources page when clicking on these links.

The Official Source: Mercedes-Benz STAR TekInfo

STAR TekInfo is Mercedes-Benz USA’s own portal for service and repair documentation and parts information, and it is where the factory wiring diagrams and parts diagrams actually live. It is not free: you register for an account and pay for access by subscription. For a single repair that is still far cheaper than a dealer diagnostic hour, and the diagram you get is the factory one for your exact model and chassis rather than a close match. The three free third party sites this page used to list, BBB Motor, AutoLib and the Eckler’s parts diagram search, have all gone offline, so we removed them rather than send you to dead pages. If you know of a live free source that is worth adding, please send us an email.

Free Fuse Box Charts and Electrical Guides on This Site

Most wiring questions start at the fuse box, and those charts are free here. Each guide shows where every fuse box is on that chassis and what each fuse feeds:

• C-Class: W203, W204
• CLA: C117
• E-Class: W210, W211, 2003 to 2008, W212 and S212, 2010 to 2016
• CLS: 2006 to 2011, W218, 2012 to 2016
• S-Class and CL-Class: W220 and C215, W221
• SL: R230
• ML and GLE: ML320, ML350 and ML500, 1998 to 2005, W164, W166, 2012 on
• GL: X164
• R-Class: W251
• G-Class: W463

If a fuse is good and the circuit is still dead, or a fuse keeps blowing, the guide to mysterious Mercedes electrical problems covers the grounds, water damage and module faults that a fuse chart cannot show you.

Digital Multimeter

The following video explains the basics of how to use a digital multimeter.

When the Diagram and the Meter Are Not Enough

A wiring diagram tells you how a circuit is supposed to work, and a multimeter tells you whether power and ground are where they should be. What neither shows you is what the car’s own control units have already recorded. On a modern Mercedes almost every circuit runs through a module, the SAM units, the engine and transmission controllers, the body and comfort modules, and when a wire chafes through or a connector corrodes, the module on that circuit stores a fault that names the circuit and the kind of failure: open circuit, short to ground or short to battery voltage. Reading that first turns a diagram with hundreds of lines into a search of one or two. A full system scanner that reads every Mercedes module, such as the YOUCANIC UCAN-II Pro, also lets you run an actuation from the module to drive the component directly, which separates a dead component from dead wiring before you open any harness. Read the modules first, then pick the right page of the diagram, then bring out the meter.