Best Resources For Automotive Wiring Diagnostics

Wiring issues are harder than ever to diagnose

At one point, just about anyone could figure out the wiring on their car or truck. It was a simple two or three wire system and tracing them was fairly easy. In 2023, every electrical feature of an automobile is connected by a module. Each module uses 12V wiring to communicate with and signal each other. An ABS light can now be caused by something unrelated to the anti-lock brake system. This is caused when the wiring and modules are tied together.  

These new technologies have even the most veteran auto mechanics struggling. Often they try to learn the best resources for automotive wiring and diagnostics. 

Every wire can cause a problem on newer cars and trucks

When manufacturers design cars and trucks, wiring is one of the most important parts to get right, but the complexity of the features consumers demand in 2023 leave a lot of room for error.

Combinations of heat, vibration, rodents and other elemental factors can cause wiring to corrode, break or melt. These types of wiring issues give us techs a massive headache.

One of the most common causes of a wiring problem in any piece of equipment comes from a prior “repair”. Mechanics without proper resources to diagnose and repair wiring problems will often “cob” a wiring harness. It’s not uncommon to see these wiring “fixes” come back as bigger electrical gremlins. 

How to avoid mistakes when diagnosing wiring problems in cars?

If you are not familiar with the way automotive electronics work, it’s best to avoid trying to make any wiring repairs. I say this because the potential for new wiring problems after a repair is very real. If you are going to attempt a DIY wiring repair on a car though, you should at least have access to the best possible resources. 

Here are the most popular resources for automotive wiring and electronic diagnosis.

  • Alldata DIY

I consider Alldata DIY to be one of the top wiring and electrical resources for diagrams, troubleshooting and more.

The main reason Alldata DIY tops my list of resources is because the program allows owners to access manufacturer information for specific vehicles. Having this affordable option for wiring diagrams is a huge advantage. Especially when trying to diagnose an electrical issue on your own vehicle. 

  • Mitchell ProDemand

I gave an option for DIY wiring diagrams with Alldata, but if you are looking to service multiple vehicles- say professionally- you’re going to need more detailed and accessible wiring diagrams and schematics. That’s where ProDemand comes in.

Owned and operated by Snap On tools, Mitchell 1 has maintained the same level of quality as the hand tools offered by Snap On. Only now they have applied their quality standards to wiring diagrams, code and symptom tips as well as many other automotive resources with the ProDemand software. If you are a professional technician, especially independent, I can’t see a reason for you to not utilize Mitchell’s services.

With an expansive database of verified fixes and the best wiring schematics available, ProDemand is a go to for independent techs that lack the resources offered by brand specific dealers. 

A three month free trial offer right now should make signing up for Mitchell ProDemand even more enticing.

  • eAuto Repair

eAuto Repair is Mitchell’s answer to AllData DIY. With vehicle specific wiring schematics and service manual information, eAuto Repair is marketed at the Do-it-yourself folks trying to diagnose and repair their own electrical problems.

With the ability to perform many of the same functions as Mitchell, eAutoRepair offers code and symptom tips as well as emission diagrams and troubleshooting procedures specific to your vehicle.

These new single car diagnostic options are making life much easier on the people working on personal vehicles in their garage. Let’s face it, professional auto diagnosis and repair is expensive. Having options when trying to figure out that pesky wiring symptom becomes invaluable.

  • Identifix

Admittedly, I have not test tested out Identifix and I’m not really sure why. The massive amount of positive reviews for Identifix out there has me suspecting it will only be a matter of time before I test out Identifix. Especially since I just learned they also offer a free 7-day trial to their Direct-Hit platform.

While researching for this post, I also learned that Identifix offers single vehicle options for the DIY backyard mechanics. With the wealth of knowledge and troubleshooting tips for cars/trucks, I have no doubts that Identifix will be an essential tool in diagnosing and repairing automotive electrical systems.

Fully electric cars will make diagnosis harder.

The above resources for wiring diagrams, code and symptom tips, and other manufacturer specific information are very useful now. With the eventual take over of fully electric vehicles, figuring out a wiring problem in your car will become even more frustrating and likely impossible for the backyard mechanics we know and love.

For now though, these automotive wiring and electrical resources are going to make diagnosing your cars emissions, wiring and sensor issues much easier.


By John Green

I’m John Green. I’m a 33 year old auto technician from Upstate New York. I have 18 years of experience as an automotive light duty and heavy duty truck mechanic. Cars, trucks and anything with moving parts are my passion in my professional life.

Aside from my life as a technician, I am also a seasoned investor and consider myself very financially literate. I use this other passion combined with my passion for cars, trucks and tools to look for ways to save money for my technician friends.

Raising my three girls and teaching them the proper way of life is my personal passion in life. If you want to know more, just ask! I’m on Twitter, Facebook and YouTube as well!