Our Story
Built by Experience. Designed for Real Work.
Trailer Dr. was founded by Bruce Theriault, an equipment professional whose career spans more than 30 years working hands-on with semi-trucks, trailers, and heavy equipment in the trucking and forestry industries.
Trailer Dr. was built from firsthand experience maintaining equipment in demanding environments where downtime is expensive and reliability is critical. The goal from the beginning was to create a diagnostic tool that is durable, straightforward to use, and supported by people who stand behind it. Not a call center.
Philosophy
A Practical Approach to Trailer Diagnostics
Trailer Dr. focuses on the trailer systems that most often lead to inspection failures, downtime, and safety concerns. Rather than adding layers of software or unnecessary complexity, the product is designed to help technicians verify electrical and air brake performance quickly and confidently, right where problems occur.
The most compact and most powerful trailer diagnostic tool in its class: 30A output, 15.2 lbs, fully waterproof, and ready to work without apps, tablets, or Bluetooth pairing.
Built for the Field
Built for the Conditions You Actually Work In
Trailer Dr. is built to perform in real working environments across the United States: shops, fleet yards, and mobile roadside operations. Not controlled lab settings.
Rugged Construction
Aluminum cabinet with waterproof NEMA-rated polycarbonate enclosure built to handle real field conditions.
Compact and Easy to Move
At 15.2 lbs with a built-in handle, it moves easily between trailers in any shop or yard. Works with any 115V outlet and air supply.
All-Weather Operation
Reliable in cold, wet, dusty, and harsh conditions. Built for real environments, not controlled lab settings.
No Software Required
No apps, tablets, or Bluetooth pairing. Plug in, connect, test. That is it.
Used by fleets, repair shops, and mobile service operators across a wide range of industries nationwide, in shops, yards, roadside, and on service vehicles.
How We Compare
Smallest Unit. Most Power. No Compromises.
Competing trailer testers are bulkier, less powerful, or require software and vehicle mounting. Trailer Dr. was built to outperform them all in the conditions that actually matter.
2/3rds More Power
30A output at 12.8 VDC. More power means more reliable testing across a wider range of trailer configurations and conditions.
Smallest in Its Class
12 x 10 x 4 in, 15.2 lbs, fully waterproof. Competitors are bigger, heavier, and not rated for the elements.
Total Flexibility
Works stand-alone or mounted to a service vehicle. Competitors that require vehicle mounting can't say the same.
No Software, Ever
No apps, no subscriptions, no pairing. Optional rechargeable remote with integrated work light adds capability without complexity.
Support
Service That Reflects Accountability
Support and service are a core part of the product. Trailer Dr. is backed by a 1-year warranty with a 48-hour repair turnaround designed to reduce downtime and keep customers working.
Customer support comes directly from the people who build and understand the product. The focus is on resolving issues quickly and standing behind the tool long after the sale.
Covers every unit
Back in your hands fast
From the people who build it
Fort Kent, Maine
Continuous Improvement Driven by Real Feedback
Trailer Dr. continues to evolve based on real-world use. Feedback from technicians, fleet operators, and service providers plays a direct role in refining the product.
Suggestions and improvement ideas are welcomed. The goal is not just to sell a tool, but to keep making it better for the people who rely on it.
Share FeedbackProfessional Trailer Diagnostics, Built to Last
Trailer Dr. provides a practical solution for diagnosing trailer lighting, air, and brake systems with a single, durable tool. Simplicity, reliability, and real-world performance. Built in Maine, used nationwide.
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