Troubleshooting semitrailer electrical operations

June 12, 2017
What to know.

A number of technological innovations over the course of the past two decades have dramatically altered the makeup and performance of a semitrailer electrical operation. Such innovations include the wiring harness, LED lighting and anti-lock braking systems (ABS). More recent features include tracking devices, sensing devices and tire inflation capabilities.

“These added features as an integrated system demand new and better testing tools and methods, replacing the famous switch box and the technician’s best guess” says Bob Blair, president and founder, Lite-Check Fleet Solutions (, a provider of trailer diagnostics. “The technician needs to know the voltage and the condition of the circuits to be displayed.”

According to Blair, electronic testing tools with dedicated software and digital readout are absolutely required to assist with identifying circuit issues and reading the ABS control unit.

“These tools take the guesswork out of the repair with consistent information,” Blair says. 


Blair credits a Technology & Maintenance Council (TMC) member survey from several years back with detailing characteristics maintenance personnel should look for in the tools they buy. He says these characteristics are applicable to what technicians should seek out of the product offerings designed to service electrical operations. Those characteristics are:

  • Easy to use
  • Rapid payback within a year
  • Solves multiple issues
  • Durable for shop or mobile use
  • Upgradeable – extending the life and applications
  • Vendor support and service

TMC ( is an organization dedicated to improving transport equipment, its maintenance and maintenance management. 

Blair believes the future of semitrailer electrical operation maintenance starts with being able to effectively manage data.

"Historically, the trailer was the forgotten sister to the tractor, even though the trailer was the revenue generator,” he says. “Technology is now available to collect the trailer elements – electrical, air, ABS, tires – automatically on a tablet in the shop, and the tablet app directs the technician through the process to produce a U.S. DOT inspection in a file for a printed report and data collection.”

About the Author

Mike Schmidt

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