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November 8, 2022 / by Identifix Auto Repair Professionals

How to read an automotive wiring diagram

Automotive wiring diagrams are valuable resources for locating, diagnosing, and fixing any automotive electrical problem. At first sight, wiring diagrams can appear intimidating and complex – especially book-bound wiring diagrams. However, reading and interpreting wiring diagrams becomes much easier with the right technology.

Reading an automotive wiring diagram the traditional way

An automotive wiring diagram is like a road map. But instead of showing the routes and destinations of a geographical area, it helps you navigate vehicle electrical systems, sub-systems, individual circuits, and component interconnections. With traditional wiring diagrams, it can be challenging to find the suitable component every time. That’s where technology comes in. 

In the 1960s, vehicle wiring diagrams usually consisted of a few pages in a service manual. Eventually, during the 1980s, developments in onboard electronics and other technical automotive advances made automotive electrical systems more complex. This resulted in thicker service manuals with multiple pages illustrating various tiers of the car’s electrical system.

Now technicians had to spend more time browsing through thick service manuals to diagnose and fix vehicle electrical problems. Additionally, they also had to redirect some of their mental energy to:

It wasn’t until the 1990s that digital media and online services began to replace printed service manuals as an automotive wiring diagram reference source. Today, these solutions use the best in modern technology to eliminate the pain of reading book-bound diagrams while also providing technicians with more advanced features and benefits.

How do color codes and symbols help in reading automobile wiring diagrams?

Automotive manufacturers use symbols to help technicians identify various circuit components in their wiring diagrams. They also use color codes to identify wires and numbers and label the circuits. Although these visual aids are beneficial, they can be confusing without the right reference tools.

This is why the legend is vital to reading one of these diagrams. Usually positioned at the beginning of the wiring manual, the legend contains a graphic list of symbols and their two- to four-word definitions. For example, the legend may display the following:

The right technology eliminates the hassle of moving back and forth between the legend and the wiring diagram you’re working with. It’s much easier to identify components with the legend and the diagram side by side.

How technology makes it easy to read and trace wiring diagrams

Traditional book-bound wiring diagrams usually have numerous pages. As a result, you can spend considerable time flipping through page after page of wiring diagrams. Plus, manual page surfing can cause you to lose your place or force you to start over.

Even if you could fit all the wiring information on one large, fold-out page, the paper wiring diagram would be unreadable. The right digital solution provides the best remedy for this problem by offering you the option of a side-by-side or single-page view of multiple wiring diagrams.

For example, Direct-Hit® repair software by Solera Identifix provides this option and covers more than 85% of the automobiles currently on the streets. Along with enhancing your page formatting capabilities, Direct-Hit leads other shop solutions by providing the following:

Plus, Direct-Hit gives you access to over three million verified and confirm fixes. These fixes are submitted by expert technicians and are instantly searchable by symptom, keywords, vehicle, or Diagnostic Trouble Code (DTC).

Maximizing the use of automotive wiring diagrams with auto repair software

Regardless of how intricate and intimidating an automotive wiring diagram looks, you can decipher it by remembering two basic principles: The wiring must form a circle for the voltage to flow, and the voltage will always seek the shortest path to ground.

In addition, you can use the technology provided by Solera Indentifix Direct-Hit® auto repair software to make reading wiring diagrams much easier and more convenient. If you want to learn more about Direct Hit’s shop solutions, visit