Wiring & Electrical Fault Finding
Some of the hardest faults to find are wiring faults. We trace them properly — continuity, voltage drop, scope work and visual inspection — then repair them to a standard that lasts.
Symptoms of a Wiring Fault
Wiring faults are often the most frustrating — they can mimic a failed module, come and go with the weather, and defeat generic scan tools. Look out for:
- Electrical faults that come and go — often weather or temperature related
- Warning lights for systems that appear unrelated to each other
- Blown fuses that keep blowing, or fuses that have been replaced with the wrong rating
- Burning smell, scorch marks or visible damage to a wiring loom
- Water ingress in connectors — particularly after heavy rain
- CAN bus or communication faults logged across multiple modules
- Faults that other garages have been unable to trace
How We Trace It
A fault code points at a circuit. Working out exactly where on that circuit the fault lies is the real job:
- Start with the fault code, then follow the wiring diagram — not the other way round
- Continuity and resistance testing across the relevant circuit, including under load
- Voltage drop testing on earth points and power feeds — a poor earth is one of the most common causes of phantom electrical faults
- Visual inspection of looms, connectors and grommets for damage, corrosion or water ingress
- Scope work where required to look at CAN and LIN bus signals properly
- No guesswork: we identify the exact location of the fault before any repair is carried out
What the Repair Involves
Wiring harness repair
Repair of damaged sections of loom — properly soldered and protected, not twisted and taped. We use manufacturer-grade crimps and heat-shrink.
Connector & pin repair
Replacement of corroded or damaged pins, sockets and connectors — the small parts that cause a disproportionate number of electrical faults.
CAN & LIN bus repair
Diagnosis and repair of communication network faults — twisted-pair integrity, terminating resistors and module isolation.
Earth point restoration
Cleaning and re-making of earth points and chassis connections, which resolve a surprising number of otherwise inexplicable faults.
Helpful Information
Wiring faults are easier to trace when we know the conditions that trigger them. When you get in touch, it helps to mention:
- Whether the fault is constant or intermittent
- Whether it's worse in wet weather or after the car has warmed up
- Any recent work on the vehicle — even unrelated repairs can disturb a loom
- How long the fault has been present and whether it's getting worse
Submit these details through our contact form or call 07484 521430.
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Tell us about your vehicle and the symptoms you're seeing. We'll come back to you with the next steps.