Visual inspection
* Inspect all wiring harness, connectors, fuses and relays for damage, corrosion or loose connections.
* Check the condition of the battery, including terminal corrosion and electrolyte density.
* Inspect the alternator and starter for signs of damage or wear.
Circuit tester
* Use a circuit tester to check the continuity of wires and connectors.
* Check the voltages at the terminals of components such as sensors, actuators and control modules.
Diagnostic scanner
* Connect the diagnostic scanner to the vehicle’s OBD-II port.
* Read fault codes from all control modules.
* Interpret fault codes to determine the possible cause of the problem.
Multimeter
* Use a multimeter to measure voltage, current and resistance at various points in the electrical system.
* Check voltage drops on wires and components.
* Measure the resistance of sensors, actuators and other electrical components.
Oscilloscope
* Use an oscilloscope to analyze electrical signals such as sensor waveforms and control module outputs.
* This will help diagnose temporary or intermittent faults.
Load fork test
* Use the load fork test to check the capacity and condition of the battery.
* Apply a load to the battery terminals and measure the voltage.
Test of the old
* Use the old test to check the condition of the starter and alternator.
* Measure the starter speed and generator output voltage.
Other diagnostic methods
* Diagnosis by listening: using a stethoscope to listen for unusual noises in the electrical system.
* Smell diagnostics: Looks for specific odors, such as burning smells, that may indicate a problem.
* Touch diagnostics: Gently touch components to detect heat or vibration, which may indicate a problem.
Precautions
* Disconnect the battery before performing any diagnostic work.
* Wear protective equipment such as goggles and gloves.
* Be careful when handling electrical components as they may contain high voltage.
*Seek help from a qualified professional if you are unsure of your diagnostic abilities.