Seven troubleshooting methods for truck circuit faults, quickly diagnose truck circuit faults
Feb 14, 2022
Frequent daily use of the truck will inevitably cause some minor failures, especially the circuit failure of the truck. Sometimes drivers don't know where the fault is, let alone troubleshooting it quickly. Common faults in truck circuits are: open circuit, short circuit, damage to electrical equipment, etc. Here are some tips to teach you how to troubleshoot circuit faults yourself.
1. Intuitive diagnosis method
When the truck circuit breaks down, abnormal phenomena such as smoke, sparks, abnormal noise, burnt smell, heat, etc. sometimes occur. These phenomena can be directly observed, so that the location of the fault can be judged.
2. Open circuit method
When a ground fault occurs in the truck's circuit equipment, it can be judged by the open circuit method. Disconnect the suspected ground fault circuit section and observe whether the ground fault still exists in the electrical equipment to determine the location and cause of the circuit ground fault.
3. Short circuit method
An open circuit fault in the truck circuit can also be judged by the short circuit method. Use a screwdriver or wire to short-circuit the circuit suspected of having an open circuit fault, and observe the indicator changes of the meter or the working condition of electrical equipment to determine whether there is an open circuit fault in the circuit.
4. Light test
The light test method is to use a car bulb as a test light to check whether there is an open circuit fault in the circuit.
5. Instrument test method
Observe the indications of the ammeter, water temperature gauge, fuel gauge, oil pressure gauge, etc. on the truck dashboard to determine whether there is a fault in the circuit. For example, when the engine is cold and the ignition switch is turned on, the water temperature gauge indicates that the full scale position does not move, indicating that the water temperature gauge sensor is faulty or the line has ground.
6. Low-voltage grounding test method
Remove a wire end of the electrical equipment, and test the metal part of the truck to produce sparks to judge. This method is relatively simple and is often used by truck electricians. The grounding method can be divided into direct grounding and indirect grounding. It should be noted that this method cannot be applied to electronic circuit trucks.
Direct grounding method:
It is the direct grounding without load to produce strong sparks. For example, if we want to judge whether the circuit from the ignition coil to the battery is faulty, we can remove the wire connecting the ignition switch on the ignition coil and scratch it on the truck body or frame. If there is a strong spark, the circuit is normal; if no Sparks are generated, indicating that there is an open circuit in this section of the circuit.
Indirect grounding method:
It is to judge whether there is a fault in the line or load through a certain load of the truck electrical appliance and a weak spark generated by the grounding. For example, if you ground the traditional ignition system breaker connection line, if there is a spark, it means that the line is normal; if there is no spark, it means that the circuit is open.
7. High pressure test
Conduct a grounding test on the high-voltage circuit, observe the electric spark condition, and judge the working condition of the ignition system. The specific method is: remove the high-voltage wire of the ignition coil or spark plug, align it with the spark plug or cylinder head, etc., at a distance of about 5mm, then turn on the start switch, turn the engine, and observe the spark generated by it. If the spark is strong, sky blue, and the sparking sound is loud, it indicates that the ignition system is working normally; otherwise, it indicates that the ignition system is not working properly.
