Seven Troubleshooting Methods for Truck Circuit Failures

Trucks on the road every day will inevitably have some small faults, especially the circuit faults of the trucks. Sometimes there is no way to know where the faults are, let alone quick troubleshooting. The common faults of truck circuits are: open circuit, short circuit , damage to electrical equipment, etc. Here are a few tricks to teach you how to troubleshoot circuit faults yourself.

1. Intuitive diagnosis method

When the truck circuit fails, there are sometimes abnormal phenomena such as smoke, sparks, abnormal noise, burning smell, and heat. These phenomena can be directly observed, so that the fault location can be determined.

2. Circuit break method

When a ground fault occurs in the truck's circuit equipment, the circuit breaker method can be used to judge. After disconnecting the circuit segment suspected of having a ground fault, observe whether the ground fault still exists in the electrical equipment, so as to determine the location and cause of the circuit grounding.

3. Short circuit method

If there is an open circuit fault in the truck circuit, it 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, observe the change of the instrument pointer or the working condition of the electrical equipment, so as to determine whether there is an open circuit fault in the circuit.

4.  Lamp test

The test light method is to use a car light bulb as a test light to check whether there is an open circuit fault in the circuit.

5. Instrumentation method

Observe the indications of the ammeter, water temperature gauge, fuel gauge, oil pressure gauge, etc. on the dashboard of the truck 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 fire test method

Remove a certain wire of the electrical equipment and test the metal part of the truck to generate sparks to judge. This method is relatively simple and is often used by the majority of truck electricians. The grounding test method can be divided into two types: direct grounding and indirect grounding. Of particular note is that the fire test method cannot be applied on electronic circuit trucks.

Direct grounding method:

It is the direct grounding without a load to generate a strong spark. For example, if we want to judge whether the circuit from the ignition coil to the battery is faulty, we can remove the wire head connected to 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 there is no sparks are generated, indicating that there is an open circuit in this section of the circuit.

Indirect grounding method:

When the truck circuit equipment overlap fault occurs, the disconnection method can be used to determine whether the suspected overlap fault circuit section is disconnected, observe whether the overlap fault still exists in the electrical equipment, so as to determine the part of the circuit overlap and the cause.

7. High-voltage circuit grounding test method

Conduct a grounding test on the high-voltage circuit, observe the 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., about 5mm away, then turn on the start switch, turn the engine, and see if it flashes. If the spark is strong, it is sky blue, and the jumping sound is loud, it means that the ignition system is basically working normally; otherwise, it means that the ignition system is not working properly.