A multimeter can be used to detect and diagnose automotive faults.
In the process of car maintenance, there is also a risk in detecting resistance. Therefore, in car design, it is stipulated that the airbag system uses a yellow warning color to distinguish it from other system circuits. For friends who want to learn auto repair technology, they need to understand the language on the car. The yellow warning color cannot be used to detect the resistance range of a multimeter.
Be extremely careful when checking the resistance of a car, especially for beginners, as there is a risk involved. The airbag system of a car uses ignition to detonate the medication in the airbag. If we do not know whether the measured system is connected to the airbag and mistakenly detect the airbag ignition resistance, it may detonate the airbag. If we accidentally detonate the airbag, it may cause losses to the owner and even harm ourselves!
In order to avoid this situation, cars worldwide use yellow wire tubes and yellow plugs to remind maintenance and inspection personnel. Yellow is the wire and connector related to airbags, and it is prohibited to measure the wire harness inside the yellow wire tube by measuring resistance or to measure the wire on the yellow plug by measuring resistance.
In addition to considering the safety of ourselves and our vehicles, we also need to understand the language of cars. Cars are like patients, and our maintenance personnel are car doctors. Doctors should have "medical ethics".
1. When using a multimeter to detect and diagnose car faults, three methods of measuring voltage, resistance, and current can be selected according to the needs. For beginners, the safest detection method is to use the method of measuring voltage, which has the least impact on the circuit unless careful to short-circuit the measured circuit. Secondly, when measuring current, it is necessary to connect a multimeter in series with the circuit to obtain the correct measurement result. It should be noted that after the measurement is completed, the multimeter should be restored to the state of detecting voltage as soon as possible to prevent accidental short circuit during the next measurement. This is very important during on-site maintenance!
2. Develop good measurement habits, do not use needle puncture to break the thread skin for testing, and do not leave any hidden dangers for the tested vehicles. Because after puncturing the wire sheath with a needle, although the needle hole is small, it will introduce moisture into the wire over time, causing corrosion and rust of the wire core. Over time, it will lead to poor contact and cause new faults. Although this process usually takes a long time, as a professional technician, it is only allowed to cure the "disease" on the vehicle and not to add new potential faults. This is a matter of professional ethics! In terms of details, it also includes restoring the disassembled fixing clip to normal and restoring the peeled insulation layer to normal.
