What are the methods for automotive circuit maintenance and inspection?

[OKeira]

Here are the methods for automotive circuit maintenance and inspection: 1. Visual Diagnosis Method: When a car circuit malfunctions, abnormal phenomena such as smoke, sparks, unusual noises, burnt smells, or overheating may occur. These phenomena can be directly observed to determine the location of the fault. 2. Open Circuit Method: When a short circuit (grounding) fault occurs in automotive circuit equipment, the open circuit method can be used for judgment. By disconnecting the suspected circuit section and observing whether the grounding fault persists in the electrical equipment, the location and cause of the circuit grounding can be determined. 3. Short Circuit Method: For open circuit faults in automotive circuits, the short circuit method can also be used. This involves short-circuiting the suspected open circuit section with a screwdriver or wire and observing changes in the instrument pointer or the working condition of the electrical equipment to determine if there is an open circuit fault. 4. Test Lamp Method: This method uses an automotive bulb as a test lamp to check for open circuit faults in the circuit. 5. Instrument Method: Observe the indications on the car's instrument panel, such as the ammeter, water temperature gauge, fuel gauge, and oil pressure gauge, to determine if there is a circuit fault. For example, if the water temperature gauge shows full scale and does not move when the ignition switch is turned on with the engine cold, it indicates a fault in the water temperature sensor or a grounding in the circuit. 6. Low-Voltage Grounding Spark Test Method: This involves removing a wire from the electrical equipment and touching it to the car's metal part (grounding) to produce sparks for judgment. This method is relatively simple and commonly used by automotive electricians. The grounding spark test can be divided into direct grounding and indirect grounding. Direct grounding produces strong sparks without passing through a load. For example, to check if the circuit from the ignition coil to the battery is faulty, disconnect the wire connecting the ignition switch from the ignition coil and scrape it against the car body or frame. If there are strong sparks, the circuit is normal; if not, there is an open circuit. Indirect grounding produces weak sparks through a load to determine if there is a fault in the circuit or load. For example, grounding the connection wire of a traditional ignition system breaker. If sparks occur, the circuit is normal; if not, there is an open circuit. It is important to note that the spark test method should not be used on electronic circuit vehicles. 7. High-Voltage Spark Test Method: Perform a grounding spark test on the high-voltage circuit and observe the spark condition to judge the working condition of the ignition system.