Troubleshooting automotive electrical faults requires following a systematic process. First, conduct a visual inspection to check for obvious abnormalities such as damaged wire insulation, oxidized plugs, or blown fuses, with special attention to hidden issues like corroded relay contacts or poor switch connections. Use a multimeter to measure key parameters: the battery voltage should be stable at 12V (engine off) or 13.5-14.5V (engine running); abnormal readings may indicate a generator or grounding fault. A test light is suitable for quickly verifying circuit continuity, while a diagnostic tool can read ECU fault codes to accurately locate electronic system problems. For complex faults, troubleshooting should be done in sections based on circuit diagrams—for example, dividing the system into modules like power supply, ignition, and lighting. Use the replacement method to verify suspicious components (such as spark plugs) and eliminate interference by simplifying the circuit. For safety, always disconnect the negative battery terminal first; high-voltage system maintenance requires professional protection to avoid short-circuit risks. With the increasing integration of modern vehicle electrical systems, it is recommended to prioritize checking vulnerable parts like fuse boxes and wiring harness connectors, and pay attention to sensory clues such as abnormal noises or burning smells. During professional repairs, low-voltage grounding tests are used to check conductivity, or high-voltage spark tests to assess ignition coil performance. These methods need to be combined with logical reasoning to gradually narrow down the fault scope.
