Electrical
Diagnostics And Repair

Electrical diagnosis at Torpedo begins with a full scan of all on-board control modules — engine, transmission, ABS, body controller, instrument cluster, and aftertreatment. We read active and stored fault codes from every module, not just the primary ECM, to build a complete picture of the truck’s electrical health before any repair recommendation is made.

Beyond fault codes, we perform live data monitoring to observe sensor values, voltage references, and signal patterns under operating conditions. A fault code points toward a circuit — live data identifies the specific component causing the fault. This approach eliminates the guesswork that leads to repeated part replacements without resolution.

• All fault codes documented before any repair begins
• Module communication network (CAN bus) tested for integrity
• Post-repair scan confirms all fault codes cleared and no new codes set

Wiring harness inspection and repair is performed using wiring diagrams specific to the truck’s make, model, and year. We trace circuits from the power source through the fuse and relay center to the load component — identifying opens, shorts, and high-resistance connections that cannot be found by swapping parts alone.

Harness repair is performed using heat-shrink solder connectors, OEM-grade terminals, and proper loom protection to match the original build quality. Wire splices are never performed with twist-and-tape connections — every repair is sealed and protected against moisture and vibration to prevent repeat failures at the repair point.

• Pinpoint voltage drop testing performed at every connection point
• Connector terminals inspected for corrosion and back-out
• Repaired harness sections re-routed and secured to original loom path

Alternator diagnosis covers AC ripple output, DC output voltage under load, and regulator function. An alternator that passes a no-load bench test may still fail under the full electrical demand of a loaded truck — we perform the diagnostic under operating conditions to confirm the charging system can sustain the truck’s full electrical load.

Battery testing on Class 8 trucks covers all batteries in the bank using a conductance tester that measures cold-cranking amp capacity without requiring a full discharge. We test each battery individually and as a bank, identifying weak batteries that pass a visual inspection but drop voltage below cranking threshold under load.

• Battery cable ends inspected and cleaned with every charging system job
• Ground straps and frame grounds tested for resistance
• Belt and tensioner inspected with every alternator replacement

Starter diagnosis covers voltage at the starter solenoid during cranking, ground circuit resistance, and starter draw current. A starter that cranks slowly or intermittently fails may have an internal electrical fault, a failed solenoid, or a high-resistance ground connection — current draw testing distinguishes between these causes before replacement.

Starter circuit testing includes the battery disconnect switch, main battery cables, and the starter relay. Corroded or undersized battery cables are one of the most common causes of hard starting and starter failure on Class 8 trucks, and they are an item that is routinely replaced to resolve no-start conditions that new starters alone do not fix.

• No-start conditions diagnosed before any parts are ordered
• Flywheel ring gear inspected for damage with every starter replacement
• Starting system performance verified under load after repair

DOT lighting compliance inspection covers all required running lights, brake lights, turn signals, reflectors, and marker lights on both tractor and trailer. We perform a full lighting audit using a systematic check of all circuits — identifying failed bulbs, corroded sockets, and broken wiring that create DOT violations and unsafe road conditions.

Headlight and work light system repairs cover sealed beam and LED housing replacements, aim adjustment, and wiring connector inspection. Trailers with damaged lighting harnesses from previous repairs are rewired clean — not patched — to restore reliable lighting that does not intermittently fail on the road.

• Trailer 7-pin plug and socket tested and replaced if corroded
• Turn signal and brake light timing verified with a scope
• All lighting circuits confirmed operational before truck and trailer release

Sensor replacement at Torpedo is performed only after the sensor circuit has been tested and the sensor confirmed faulty — not replaced on suspicion. We measure reference voltage, ground, and signal output at the sensor connector before condemning the sensor, eliminating unnecessary replacements and ensuring the actual cause of the fault code is addressed.

Control module programming and software updates are performed using OEM diagnostic tools. Some fault codes and driveability complaints are caused by outdated ECM or transmission control module software — a software update resolves the issue without replacing any hardware. We check for applicable software updates before recommending module replacement.

• Sensor calibration performed where required after replacement
• Module parameter reset and initialization completed after programming
• Electrical system verification test run after all sensor and module work