Rick's Free Auto Repair Advice

Find free wiring diagrams

Where to get a free wiring diagram

Answer: Nowhere.

Lots of people ask for free wiring diagrams in auto forums.

First off, even if I have access to those diagrams, it’s illegal to just copy them and send them to someone else. I know copyright infringement isn’t really thought of as a serious crime these days. But why would I risk the dreaded lawsuit for somebody I don’t even know—somebody who isn’t willing to spend a few bucks to get the right information to fix their car in order to save several hundred bucks?

But more than that, there’s no such thing as a single wiring diagram for a vehicle. The diagrams vary by engine size, options, whether the vehicle has daytime running lights, automatic temp control, etc. In other words, unless you specify that you want a free wiring diagram for your specific vehicle, there’s simply no way you’re going to find the correct one. Trying to track down a headlight problem? Well, if you find a free wiring diagram for a vehicle with daytime running lights and your vehicle doesn’t have them, you’ll be screwed.

It just isn’t that expensive to subscribe to an online service and get the real information for your specific vehicle from a reliable source. In addition, the solution to the problem you’re trying to solve may already be in a technical service bulletin put out by the car maker. In that case you’d be wasting a ton of time trying to track down the problem on your own. That’s why the pros ALWAYS check the TSB’s before starting any repair.

TSBs can be you best friend when it comes to fixing your car. That’s because TSBs should actually be called “Pattern Failures,” or “We Goofed and Here’s How to Fix What We Should be Fixing.”

I recommend two online services. Here are the pros and cons of each one.

Alldata has diagrams of body trim components with instructions on how to remove them. So if you have to tear into your dash, remove a door panel, or replace a window regulator, this is the service for you. Alldata also seems to have more up-to-date TSBs.

A 1-year subscription is $26.99. A 5-year subscription is $44.95. They don’t offer shorter subscription periods, but they do offer discounts for adding additional vehicles to your base subscription. Add a 1-year subscription to an additional vehicle for $16.95 or a 5-year for $29.95

Alldatadiy.com Disadvantages

In many case, the wiring diagrams are either factory diagrams or pretty darn close to factory diagrams. They are much harder to read unless you’re familiar with factory layouts. Worse yet, the wiring diagrams don’t tell you where the splices, grounds, or electrical components are located. You have to go to the component locater section to find that information. It’s cumbersome.

Also, Alldata is very skimpy on the theory and operation of how individual systems work. That kind of information can be critical to you making a successful repair.

Eautorepair.net Advantages

Eautorepair redraws all the wiring diagrams so they make more sense. They start at the top with the fuse that supplies power to the system and then follow down through the complete system. The wiring diagrams also list where each component, splice, and ground is located. So you can print out the entire diagram and have all the information in one place.

Eautorepair.net also explains the theory and operation of each system, which can be incredibly helpful if you’ve never worked on the system before. For example, Eautorepair.net explains exactly how GM’s PassLock system works, step-by-step. It tells you what each flashing light means, what systems are enabled or disabled, and how to do a “relearn” procedure.

Eautorepair.net also offers a 1-week subscription for only $11.99. So if you just need to pop in, print out a diagram or repair procedure, and be on your way, this is the best buy. They also offer a 1-year subscription for $29.99

Eautorepair.net Disadvantages

Eautorepair.net doesn’t have ANY diagrams for body or trim parts. If you need to tear into a dash, replace a window regulator, or remove a door trim panel, you’re out of luck with eautorepair.net.

The PUBLIC Library

Oh yeah, you forgot about the public library. Most now offer “in-library” use of an auto online service. It’s free, but you have to physically go to the library—no home use for this service. Libraries usually offer either Alldata, Eautorepair, Chiltons, or EBSCO. EBSCO is the least helpful of them all. However, it does offer TSBs and some wiring diagrams. I’m not a big fan of Chiltons, but if it’s free and you have no other source, it’s worth a try.


© 2012 Rick Muscoplat

Posted on by Rick Muscoplat


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