Visual inspection
* Check the battery for corrosion, cracks and loose connections.
* Inspect wires and cables for damage, fraying, or exposed areas.
* Check fuses and relays for burnout or damage.
* Inspect contacts and terminals for corrosion, dirt or looseness.
Circuit testing
* Use a multimeter to check voltage, current and resistance in circuits.
* Check continuity using a test lamp or multimeter in circuit test mode.
* Check the ground using a multimeter in resistance mode or a test lamp.
Component testing
* Check the alternator for voltage production and proper battery charging.
* Check the starter to see if it can start the engine and draw current.
* Check the spark plugs or glow plugs for spark or heat.
* Check the ignition coils for sparks or voltage pulses.
* Check sensors for correct signals (eg coolant temperature sensor, crankshaft position sensor).
Diagnosis of fault codes
*Connect the trouble code scanner to the car.
* Read and interpret fault codes to determine the problem.
*Clear fault codes and test drive to ensure the fault is resolved.
Other diagnostic methods
* Load Test: Use a load tester to simulate the load on the electrical system and identify problems with loose connections or faulty components.
* Component Removal and Installation: If necessary, remove and install components such as the alternator, starter, or ignition coils for further diagnosis or replacement.
* Using diagnostic software: Use specialized software to diagnose vehicle electronic systems, such as engine control modules or ABS systems.
Notes:
*Always perform a visual inspection first before testing.
* Observe safety precautions when working with electrical components.
* Disconnect the battery before carrying out any electrical work.
*Refer to vehicle repair manual for specific information and specifications.