Tools for diagnosing electrics in a car:

* Multimeter
* Oscilloscope (optional)
* Probe lamp (or LED test lamp)
*Car wiring diagram

Diagnostic procedures:

1. Visual inspection:

* Check for loose or damaged wires, connectors and fuses.
* Check the battery and terminals for corrosion or damage.

2. Fuse testing:

* Use a multimeter in continuity test mode to check the integrity of the fuses.
* Replace any blown fuses.

3. Voltage check:

*Use a multimeter to measure the voltage on the battery. At idle it should be around 12.6V.
* Check the voltage at various points on the circuit to ensure it is correct.

4. Current testing:

* Use the multimeter in current mode to check the current in the circuit.
*Compare readings with manufacturer’s directions.

5. Resistance testing:

* Use a multimeter in resistance mode to check the resistance in the circuit.
*Compare readings with manufacturer’s directions.

6. Grounding testing:

*Use a multimeter to check for proper grounding.
* Measure the resistance between the negative terminal of the battery and a metal part of the car frame.

7. Signal testing:

* Use an oscilloscope to test control signals (eg from the ECU), sensors and actuators.
* Compare the received signals with the reference ones.

Common car electrical faults:

*Blown fuses
* Short circuits
* Circuit breaks
* Faulty sensors and actuators
* Defective battery
*Wiring problems

Adviсe:

*Always disconnect the battery before starting diagnostics.
*Use the correct tools and follow safety precautions.
*Refer to the vehicle wiring diagram if necessary.
* If necessary, contact a qualified auto electrician.

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