Wrench Tech – March/April 2022

Electrical issues have bedeviled technicians since the beginning of the trucking age. And new systems will require even greater attention to detail in the future.

If there is one basic fact about commercial vehicle electronics that defines the core of the maintenance problem they present, it is the simple fact that they do not do well in the harsh work conditions trucks must work in.

Electrical systems, wiring, conductors and connectors do not like excessively hot or cold temperatures. They don’t like the elements. They don’t like road vibrations. And the delicate protective casings often allow water, dirt, grease, soot and other contaminants in, which quickly leads to system failure.

“Electronics have always been a pain point for fleet maintenance professionals,” says Kristi LaPage, business manager for the commercial vehicle group for Mitchell 1, a vehicle repair software provider based in Poway, Calif. “To a large extent, the electrical system has always been the nervous system of a vehicle. And they’ve always been complex and difficult to work on. Although we’ve seen a lot of advances in electronics troubleshooting over the past several years, the reality is that these systems will always be a time-consuming problem for most fleets.”

To make things even more frustrating for technicians, conditions that can cause electrical systems failures are often highly intermittent in nature, explains Jason Hedman, product manager for commercial vehicle diagnostics company Noregon, Greensboro, N.C.

For example, he said, a wire that is wet may carry a current just fine when it is dry. Likewise, a failure caused by a wiring harness vibrating rapidly at highway speeds may be undetectable when the truck is sitting still in the shop. This means that a problem can occur on the road, and be faithfully reported by the driver. And then it can’t be replicated in the fleet shop or at a third-party service supplier.

“Electrical system troubleshooting is a massive bottleneck for fleets,” said Brett Miller, engineering manager for Optronics International/USA Harness International, Tulsa, Okla. “A big problem is that many of them are still using old methods to determine what the issue is. But sticking a probe through a wire casing to see if current is getting through ultimately creates more points of entry for water, dirt and other elements that can eventually compromise an entire wiring harness. Fleets really need to adopt better ways of understanding what problems they’re facing instead of spending excessive time casting around and hoping to hit on the issue.”

Another problem is that new technology often means relearning maintenance truisms and procedures that have been in place for decades.

A good case in point, the introduction and fast adoption of new LED lighting systems on trucks has unintentionally created maintenance headaches for some fleets, Miller said.

“Conventional, incandescent light bulbs draw more power than LED bulbs – which is one of the key benefits to switching over to LED systems,” he said. “However, some self-diagnosing vehicle systems interpret that low power draw as a signal that a perfectly healthy bulb is out all the time because the old power draw simply isn’t there. And you end up with technicians chasing ghosts over a fundamental misunderstanding of the differences between LED and incandescent lighting systems.”

New tricks for old tech

New remote diagnostics now play a major role in improving vehicle safety by catching electric or lighting issues as soon as they happen – or in some cases, before a malfunction even occurs. “Advanced aftermarket diagnostic tools have not only made it easier to detect electrical issues by simultaneously scanning all components but have also improved in capabilities that assist the user with the diagnosis,” Hedman said. “Technicians can use a single application to scan the truck, locate the affected wiring harness using suggested troubleshooting steps, view the harness’s wiring diagram, and then chart data points or use relevant bidirectional commands like a wiggle test to find the damaged wire.”

Based on this new technology, Irvine, Calif.-based Phillips Connect has introduced its Light Out system, which Cliff Creech, director of sales engineering, said continually monitors the lights on a vehicle and stores a 30-day history of faults that are continually reported to fleet operations.

“When the vehicle is serviced, this information can be accessed by the technician giving him/her a clear indication of what the problem is which they can then address and fix,” he said. “This saves time and more likely results in the proper lasting repair.”

LaPage said Mitchell 1 also is leveraging new technologies, like its interactive wiring diagrams, which she says can significantly save time in diagnosing and repairing electrical problems.

“When viewing one of our wiring diagrams, technicians can click on any component or wire within the diagram to see a pop-up menu with selections to learn more about specifications, component location, connector views, guided component tests, and more,” she said. “There is no need to exit the wiring diagram to find related information needed to diagnose the issue. And if that examination turns out to be a dead-end, the technician is automatically returned to the correct diagram to continue checking for other issues – all without having to initiate a secondary search.”

Optronics’ O’Dell said that in his experience the weakest links in a truck’s electrical system are the links between wiring and vehicle systems – the molded plugs and hard-shell connectors that often attract dirt, debris or allow water inside. He recommends replacing them with more modern, and better-protected connectors as part of a prescribed, preventive maintenance regimen for your fleet.

“Most fleets simply repair lighting and electrical issues as they come up, and don’t really have a dedicated, coherent, long-term (preventive maintenance) program designed to combat these problems,” he said. “I advise fleets to establish an annual vehicle electrical inspection schedule – perhaps every two years or so, depending on your operation.” LL