Where to get a free wiring diagram
Nobody wants to spend money to get a wiring diagram. And yes, there are are a few blogs that post free wiring diagrams. But due to copyright infringement enforcement actions by the car makers, those diagrams tend to disappear shortly after they’re posted.
There are wiring diagrams and then there are the RIGHT wiring diagrams
Here’s the deal: Car makers manufacture multiple variations of every vehicle. So the engine compartment wiring diagram for a model with a V-6 engine will be different than the same model with a 4-cylinder engine. Even with the same engine, you may see different diagrams for a vehicle with an automatic versus manual transmission, 2WD and AWD, and different accessory packages. In other words, there’s no such thing as a single wiring diagram for all variation of the same year, make and model vehicle.
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.
So when you post saying “I need a free wiring diagram for a 2004 Buick,” there just no way in the world anyone can help you.
In other words, you’re not going to get much response.
Here’s the ONLY place to find free wiring diagrams
The PUBLIC Library
Oh yeah, you forgot about the public library. Most libraries have access to on-line auto repair manuals on their “in-library” computers. It’s free, but you have to physically go to the library—no home use for these services. 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.
Call your public library and ask if they have online access to an auto repair shop manual service. Then log in, find the diagrams and print them on the library printer. Total cost? Maybe $2 for the printer/copy machine.
Or, buy a subscription to a professional shop manual
Pro shops subscribe to Alldata and Mitchel on Demand. Both services sell the same information to do it yourselfers. Simply go to alldatadiy.com or eautorepair.net and buy a subscription. You’ll get the full service with technical service bulletins, wiring diagrams, step by step repair procedures, full explanations of trouble codes and and step by step testing procedures.
Yes that costs money. But you’ll be getting the right information at your fingertips. 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.”
Alldatadiy.com and eautorepair.net are the best online shop manuals
Here are the pros and cons of each one.
Alldata has diagrams of body trim components and fasteners, along 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 $29.95. A 5-year subscription is $49.95. 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 $19.95 or a 5-year for $34.95
In many case, the wiring diagrams are factory diagrams. They are much harder to read because each manufacturer uses their own special symbols. Worse yet, factory wiring diagrams don’t include the locations of splices and grounds on the same page as the diagram. So you have to go to the component locator section and find the sections for power distribution, ground locations, splice locations, etc. 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 redraws all the wiring diagrams so they make logical sense. They start at the top of the page with the fuses for each circuit and the circuit flows down through all the components, all the way to the bottom where they show you the ground. The location of each component is labeled so you don’t have to cross check. 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 also offers a 1-week subscription for only $19.95. So if you just need to pop in, print out a diagram or repair procedure, and be on your way, this is the cheapest way to get your hands on a professional manual.
They also offer a 1-year subscription for $29.95
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.
© 2012 Rick Muscoplat
Posted on by Rick Muscoplat