Commercial Truck Diagnostics & Electrical Repair Services in Edmonton, AB

Fleetgo Heavy Duty provides truck diagnostics and electrical repair in Edmonton, AB for semi trucks, commercial fleets and heavy-duty diesel equipment. A dead battery, a no-start, a check engine light or a fault that comes and goes can all trace back to the same few places: the engine control module, the charging system, the starting circuit or a corroded wire somewhere in the harness. Our technicians test before they replace, so you pay for the repair that actually fixes the truck. Diagnostics and electrical work are part of our full heavy truck repair in Edmonton, so if testing points to another system, the same team handles that repair too.

Why Accurate Truck Diagnostics Come Before Any Repair

Modern heavy trucks run on networked control modules for the engine, transmission, brakes and aftertreatment, all talking over the J1939 data link. One bad sensor, ground or connector can set codes in several systems at once, which is why guessing from symptoms so often leads to the wrong part. Proper truck diagnostics combine fault code history, live data, voltage and resistance testing, and the driver's account of when the problem shows up. That approach finds the root cause the first time, cuts repeat shop visits, and catches small electrical problems before they turn into a roadside breakdown.

Commercial Truck Diagnostic Services

Engine and ECM Diagnostics

Engine diagnostics start with OEM-level scan equipment connected to the engine's computer to read active and inactive fault codes, freeze-frame data and live sensor readings. From there our technicians test the components behind the codes, including sensors, injectors, turbo controls and EGR and DPF systems, and check engine performance under load. Fleetgo Heavy Duty also installs positive air shut-off valves and accessories that stop diesel engine runaway, and services electronic logging devices (ELDs) so your trucks stay compliant. When a diagnosis points to deeper engine work, it carries straight into our diesel engine repair and rebuild or ECM tuning services.

Transmission Diagnostics

Transmission diagnostics use the transmission control module's fault codes and live data to check shift quality, clutch engagement, oil temperature and sensor inputs on automated manual and automatic transmissions. Testing the solenoids, speed sensors and wiring connected to the transmission tells us whether a harsh or missed shift is electrical or mechanical, before any transmission or clutch repair is recommended. Our guide to transmission troubleshooting for heavy-duty trucks covers the early warning signs.

Electrical System Diagnostics

Electrical system diagnostics cover the battery bank, starter, alternator, grounds, fuses, relays, lighting and the wiring that ties them together. Using digital multimeters, carbon pile and circuit load testers, we measure charging voltage, cranking voltage drop, parasitic draw and resistance across connections. This is how intermittent faults get found. A connection that tests fine at rest can fail under vibration, load or cold, so we test circuits the way the truck actually uses them.

Semi Truck Electrical Repair Services

Once diagnostics confirm the problem, Fleetgo Heavy Duty completes the electrical repair in-shop or on site. The most common semi truck electrical repairs we handle include:

Battery Replacement and Service

A weak battery causes hard starts, low-voltage warnings and electrical faults in other systems. We load test every battery in the bank, clean and tighten terminals and cables, and replace failing batteries as a matched set so one weak battery does not drag down the new ones. Cold cranking amps matter in Edmonton, so replacements are sized for winter starts.

Starter and Alternator Repair and Replacement

The starter cranks the engine using battery power, and the alternator recharges the batteries and powers the truck once it is running. Because both depend on battery voltage, their symptoms overlap, and a failing alternator can look like a bad starter after the batteries run down. We test charging output, cranking current and the cables and solenoid between them before repairing or replacing either one. Our guide to alternator vs starter failures in commercial trucks explains how the symptoms differ.

Wiring Harness Repair and Replacement

Vibration, heat, moisture and road salt wear through insulation and corrode connectors, leading to shorts, open circuits and faults that come and go. We trace damaged circuits with wiring diagrams, repair or replace harness sections and connectors, clean and reseal grounds, and protect repairs against moisture so the same fault does not return.

Lighting System Repair and Replacement

Working headlights, marker lights, brake lights and trailer lighting are a safety and CVIP requirement. We repair lighting circuits, switches and relays, upgrade to LED where it makes sense, and fix trailer lighting problems at the 7-way connector and in the trailer harness so a lighting defect does not take a unit off the road.

Electrical Problems Made Worse by Edmonton Winters

Alberta's cold is hard on truck electrical systems. Freezing temperatures cut battery capacity at the same time a cold diesel engine needs more cranking power, and snowmelt and road salt push moisture into connectors and grounds. That is why so many electrical failures show up on the first cold mornings of the season, a pattern we break down in our comparison of operating heavy trucks in extreme cold vs extreme heat. A pre-winter battery, charging and wiring check, added to your preventive maintenance schedule or done alongside a CVIP inspection, is the easiest way to avoid a no-start. Our article on electrical system issues that lead to roadside breakdowns covers the warning signs to watch for.

Signs Your Truck Needs Diagnostics or Electrical Repair

• Slow cranking, clicking or a no-start, especially in cold weather
• Batteries that keep going dead or need frequent boosting
• Dim or flickering lights, low-voltage warnings or gauges that jump around
• A check engine or warning light, derate or limp mode
• Faults that disappear before the truck reaches the shop
• Trailer lights, ABS lamps or accessories that work some days and not others

Not every fault sets a code, and a code often names the system rather than the cause. If the same problem keeps coming back after parts have been replaced, it is time for deeper diagnostics, which we explain in our guide to intermittent faults in heavy trucks.

In-Shop and Mobile Electrical Repair in Edmonton

Many electrical repairs, including batteries, alternators, starters and wiring, can be done where the truck sits. Our mobile truck repair service covers a 100 km radius around Edmonton, including Highway 16, Sherwood Park, Spruce Grove, Fort Saskatchewan and St. Albert, and our 24/7 emergency roadside team responds when a truck will not start or loses power on the road. Work that needs extended testing, module programming or a full harness repair is completed in our Edmonton shop.

Schedule Truck Diagnostics and Electrical Repair in Edmonton

Contact Fleetgo Heavy Duty to book truck diagnostics or semi truck electrical repair in our Edmonton shop or on site, and get your truck back on the road with the problem actually fixed.