Truck electrical system diagnostics
1. Visual inspection
* Check the battery for corrosion, cracks and damage.
* Inspect cables and wiring for exposed wires, damage, and chafing.
* Check that the terminal connections are secure.
2. Battery testing
*Use a voltmeter to measure the no-load voltage (should be around 12.6V).
* Stress test the battery to determine its capacity and condition.
3. Generator testing
* Measure the voltage with the engine running (should be in the range of 13.8-14.2 V).
* Check the generator output current using an ammeter.
* Perform a diode test to rule out faulty diodes.
4. Starter testing
* Measure the voltage at the starter while starting the engine (must be at least 9 V).
* Perform a voltage drop test to check the resistance of the starter circuit.
5. Lighting system testing
* Check the operation of headlights, turn signals, brake lights and other lights.
* Measure the resistance of the lamps to check their integrity.
6. Ignition system testing
* Check the spark at the spark plugs.
* Measure the resistance and gap of the spark plugs.
* Carry out diagnostics of the ignition coil and ignition distributor.
7. Testing of sensors and control units
* Use a diagnostic scan tool to read trouble codes and check the operation of sensors (such as oil pressure sensor, coolant temperature sensor, etc.).
* Check the electrical resistance of the sensors.
8. Testing fuses and relays
* Check fuses for blown fuses by measuring resistance or using a fuse tester.
* Check the relay for proper operation and cleanliness of contacts.
9. Troubleshooting
*Use a multimeter and a truck wiring diagram to troubleshoot the system.
* Check continuity and component resistance.
* Use current tracing to track the electrical current in a system.
Tools required for diagnosis:
* Voltmeter
* Ammeter
* Omimeter
* Diagnostic scanner
* Fuse tester
* Current tracer
* Screwdriver set
* Set of keys