The battery cable is burnt out
① If only a part of the battery cable is burnt out, check the parts in contact with the burnt out part of the cable, clean the burrs, and replace the battery cable
② If all the battery cables are burned out, it indicates that the starter motor has malfunctioned Connect a test light between the positive pole of the starter electromagnetic switch and the positive pole of the battery. If the test light is on, it indicates that there is a malfunction in the electromagnetic switch; If the test light does not light up, it indicates that there is a malfunction inside the starter motor
2. The wiring harness between the generator+pole and the starter battery terminal is burnt out and the relay motor is stopped. Remove the lead wires of the generator+pole, connect a power line between the battery+pole, and the other end is in contact with the generator+pole. If sparks appear, it indicates a fault in the generator. If no sparks appear, it indicates a fault in the wiring harness
3. The wiring harness and relay leads are burnt out
① Turn off the power switch, remove the relay and let it hang in the air. Connect a test light between the relay housing and the vehicle body. If the light is on, it indicates that the relay has malfunctioned; If the light is not on, proceed with the following steps
② Turn on the power switch. If the test light does not light up, it indicates that the relay is not faulty and only the wiring harness needs to be replaced. If the test light indicates a relay fault, the relay should be replaced