Bridge the repair gap with diagnostic mentorship

Key takeaways:

• As truck diagnostics and repair continues to get more complex, it's critical to make sure new technicians have mentors they can rely on to guide them
• Successful mentorships require finding the right mentor for your shop's culture and one that can communicate with the mentee on their needs and goals
• Make sure that mentors are prepared for the position with plenty of experience, patience, and that they'll be properly compensated for their extra work

The demand for accurate diagnostics in this industry has accelerated much faster than there are technicians available with the skill set and knowledge.

Noregon’s 2025 “Unpacking the Commercial Vehicle Diagnostics Industry” report highlights the primary challenges faced by both shops and fleets. In the survey, 44% of shops and 54% of fleets listed accurately and effectively troubleshooting/diagnosing vehicle issues as a top challenge, while hiring technicians was a top challenge for 61% of shops and 48% of fleets.

My main niche was diagnostics and engine/electrical builds, so with his mentorship, I felt ready to take my ASE T6 Truck Electrical test. Unfortunately, I missed passing by a  single question. The section on starting and charging systems seemed to be a weak area.

After that, in 2022, I had the opportunity to meet  George Arrants, vice president of the ASE Education Foundation, at the ASE Instructor Training Conference. Fighting my own shame, I mustered up some courage and showed him my ASE test scores. During those moments, we discussed a variety of topics, including career and skill growth, the need for theory, and my current position in the industry. I humbly left that conversation with a goal and even more confidence.

Adamant that I needed to understand the theory of relays and PTO diagnostics better, I turned to Dougherty to improve this new skill. At first, it was challenging, as there are many different ways to wire PTO circuits.

When hardwired circuits become integrated with modules like the Transmission Controller (TCM) and/or the Body Controller (BCM), they may sometimes need to be wired and programmed. It’s important to first determine what will and will not work in the circuit instead of throwing switches, relays, and wire at the Remote Power Modules (RPMs) to the PTO without a second thought.

It took a lot of self-control not to rip it all out to install my own circuits. But through Dougherty’s perspective and insight, I realized that not every circuit is written in a diagram. This helped me become more patient and look at each circuit one at a time, rather than getting overwhelmed when adding or editing installed circuits and programming modules.

Dougherty worked with me and guided me to success, and the hard work paid off in unimagined ways. I authored two PTO circuits that were previously unwritten, hardwired, and linked through data to the TCM, while also adding a switch and relay and programming. By being able to examine those circuits more closely, I was able to get a better sense of how the circuits function, execute new electrical builds more efficiently and properly, and route my work effectively, which in turn gives the customer quality repairs and more uptime as well as a beautiful, factory-like installation.

Yes, I gained a deeper understanding of the theoretical side of a complicated system, but the most valuable lesson was the importance of passing wisdom on to the next generation.

That’s why I also started mentoring in February 2022. One of my mentees is Stepheni Trunk, who works 300 miles away at Ascendance Truck Centers. Not only do I support her with International and Cummins product diagnostics but with self-doubt as well.

“Having Missy as my mentor has helped me be less fragile and more graceful with my emotions,” Trunk told me. “I am not stupid, and I will figure it out. It’s just really refreshing to have a genuine support system.”

Through this experience, I learned something new: Mentoring is rewarding for both sides. Recently, I helped her over the phone with a fuel injector job. After she finally solved it, she told me, “Even from miles away, I could feel how proud you were, and that made me proud of myself.”

Mentoring keys to success

According to Arrants, if a shop doesn’t encourage mentorship, it’s going to have trouble keeping technicians long enough to mold them into productive diagnosticians.

“If you’re not mentoring, your success rate, or retention rate, is going to be horrible,” Arrants explained. “And if your turnover rate is over 20%, the problem is in the mirror.”

Marshall Sheldon, a mobile diesel technician at MHC Kenworth in Georgia, who has mentored apprentices for eight years, agrees. In his experience, mentorship is crucial “to having a consistent pipeline of turnkey ready-to-work technicians.”

And with the proper mentorship, you can turn techs into dedicated workers who are equally profitable and loyal to the business. “The increase in retention is immense,” Sheldon added.

Arrants also stressed a big part of mentoring for new and seasoned techs is onboarding them to their current shop’s culture, which could be very different from their previous job.

Like troubleshooting, your first option for finding the right mentor might not work. Arrants advised to have apprentices and new techs “shop around” and spend time with several possible mentors “to figure out what it is they like, or what it is they’re good at and what they are not.”

Not every tech is going to catch on to diagnostics from the start or have the time or inclination to put in the extra time it takes to be a diagnostic wiz.

“If those technicians really didn’t come from some formalized training and understand the theory side on how things work, diagnostics is very difficult,” Arrants offered.

Trunk admitted a lack of formalized training impacted her ability to pick up troubleshooting skills.

“Diagnostics is difficult for me because I didn’t go to school,” she said. “It took me over two years to finally grasp the basics of electronics.”

To find out what style technician a diagnostic apprentice is, it’s a great idea to discuss their goals up front. You may find out that their desired skill sets are ones they want to develop strongly, which may be their hardest lessons to learn.

Sheldon found that testing them in practical situations will help sort out their level and how they rise to challenges.

“When mentoring, you see quickly how a person’s mind works,” he said. “Put them into positions to see where they are weak quickly. That allows you to see if they are more mechanically driven or theory driven.”

Choosing the right mentor

“The most important decision an employer will ever make is choosing that mentor—and a lot of times they choose incorrectly or they put no thought into it,” Arrants said.

He said a successful mentor should have five to seven years in the industry and at least one year at your shop. And it’s not a temporary position.

“Mentoring is not something you do for a week or two weeks,” Arrants advised. “It’s based on the growth of the individual and their increased productivity.”

Personality-wise, they should not have a big ego, which could prevent them from teaching someone all their diagnostic secrets and eventually surpassing them.

Modeling good ethics and behavior is also important, as the mentees “pick up your good habits and your bad habits,” Arrants said.

Incentivizing mentorship

Managers should recognize that as rewarding as mentoring is, it does not pay the mortgage or grocery bills. If you officially assign a mentor, they will likely put in more effort if they are getting paid for the extra work.

According to WrenchWay’s last Voice of the Technician survey, only 26% of diesel techs said their current employer does a good job of teaching new techs and compensating mentors. That’s a drop of 15% from the previous survey, and it means that three out of four techs think their shop does a bad job at this.

Maybe we have found the root cause of why about half of the shops face labor and troubleshooting issues.

The ASE Education Foundation works with the online training provider S/P2 to certify mentors so they can get paid an hourly rate for mentoring, Arrants noted.

Sheldon said he “would love to see pay plans that drive mentorship in the right direction.”

And that direction needs to be pointed forward, as the industry needs more techs able to work with scan tools, perform volt drop tests, and trace circuits. Theoretically, they could watch videos and take all sorts of online classes to get a little better, but a computer will not help improve your confidence or give you a pep talk when you need it most.

A computer certainly cannot do for MHC Kenworth apprentice Julian Aguirre what Sheldon did.

After completing a six-month program with Sheldon, Aguirre shared, “I didn’t think I was smart enough to do everything I am doing, and I’m able to do more than I ever thought I could.”

It’s the same with Jordan Hatfield, who is an L4 diesel apprentice mentored by Sarah McCullar, an L5 diesel technician at a Love’s Travel Stop in Falkville, Alabama. “My confidence has been skyrocketing due to my mentor,” he said. “I can feel as though I can diagnose and repair properly.”

For a diagnostic tech to be successful, they have to be confident they will find the answer, even if it takes a while. And mentorship certainly provides that.