Diagnosis of vehicle electrical faults
Initial inspection
* Check the condition of the battery, make sure it is not discharged and the terminals are clean and tight.
* Inspect the fuses and relays to see if they are blown.
* Check the connectors for corrosion, looseness or damage.
Diagnostic Tools
* Multimeter
* Diagnostic scanner
* Contour lamp 12 V
*Test wire
Checking the circuit
* Use a multimeter to check for continuity in electrical circuits.
*Connect one end to one end of the chain and the other to the other.
* There must be continuous contact, otherwise the circuit is broken.
Voltage check
* Use a multimeter to check the voltage on different components.
* Set the switch to DC voltmeter position.
* Connect the red probe to the positive terminal of the component and the black probe to the negative terminal.
*Must be the correct voltage as per specifications.
Grounding check
*Use a 12V contour lamp to check grounding.
*Connect one end of the lamp to the positive terminal of the battery and the other to the component.
* If the lamp is on, there is a good ground. Otherwise, the grounding is missing or faulty.
Diagnostics using a diagnostic scanner
* Connect the scanner to the vehicle’s OBDII diagnostic connector.
* Turn on the ignition, but do not start the engine.
* Find and select the appropriate control module.
* Read fault codes and view data in real time.
Specific tests
*Generator: Check output voltage and current
* Starter: checking current consumption and rotation speed
* Ignition system: checking ignition spark and position sensors
* Fuel injection system: checking fuel pressure and control signals
Diagnostic tips
* Be systematic and methodical in your approach.
* Record your test results.
*Refer to the diagnostic and repair manual for your specific vehicle.
* If the problem cannot be corrected, contact a qualified mechanic for assistance.
* Observe all safety precautions when working with electrical components.