Possible reasons for the failure of all electrical equipment in the car:
1. Battery malfunction:
*Dead or faulty battery
* Loose or corroded battery terminals
2. Generator malfunction:
* Faulty or loose alternator belt
* Faulty voltage regulator
* Problems with diodes or windings
3. Blown fuse or relay:
* Break or blown fuse responsible for powering all electrical equipment
* Faulty relay responsible for turning electrical components on or off
4. Wiring problems:
*Frayed, damaged or disconnected wires
* Poor contacts or corrosion on connections
5. Control module malfunction:
* Faulty main control module (ECU)
*Faulty Body Control Module (BCM)
6. Other reasons:
* Faulty ignition switch
* Problems with ground wire
* Oxidation or corrosion of electrical connectors
Diagnostics and troubleshooting:
1. Check the battery: Measure the battery voltage with a voltmeter. Replace the battery if it is low or defective.
2. Check the generator: Start the engine and turn on the instruments. If the battery voltage does not increase, the alternator may be faulty.
3. Check fuses and relays: Check the fuse panel for blown fuses. Use a tester to test the relay for functionality.
4. Inspect the Wiring: Inspect the wiring under the hood and in the interior for damage, disconnections, or corrosion. Correct any problems found.
5. Check control modules: Use a diagnostic scanner to check for trouble codes. This may indicate problems with the ECU or BCM.
6. Check the ignition switch: Try starting the engine in the “accessory” position. If the electrics work, the ignition switch may be faulty.
7. Check the ground wire: Make sure the ground wire terminals are securely attached to the body and engine. Clean and tighten terminals if necessary.
8. Check electrical connectors: Disconnect and reconnect electrical connectors on various components to eliminate corrosion or poor connections.