How to Quickly Find Car Line Grounding Faults

3) Short circuit method

If there is an open circuit fault in the automobile circuit, you canalso use the short circuit method to judge, that is, use a screwdriver or wire to identify the circuit suspected of having an open circuit fault p>

and observe

changes in the meter needle

or operating conditions of electrical equipment to determine whether there is a circuit fault open in the circuit.

4)

Light test

Method

The light test method is to use a car bulb as a lamp. test to check circuit Is there a circuit breaker failure?

5) Instrumental method

Observe

the ammeter on the car dashboard

, water temperature gauge,

fuel gauge

,

oil pressure gauge

, etc., determine if there is any problem in the circuit. For example, when the engine is cold and the ignition switch is on, the compWater temperature meter indicates full scale position and does not move, indicating that the water temperature meter sensor is faulty or the circuit is grounded.

6) Low voltage earthing

Fire test

Method

That is, remove a certain wire of the electrical equipment from the metal of the car This can be judged by the sparks generated when a part (iron to ground) is touched. This method is relatively simple and is often used by the majority of auto electricians. The grounding fire test method can be divided into two types: direct grounding and indirect grounding.

So-called direct grounding means direct grounding without load to produce strong sparks. For example, if we want to determine if there is a fault in the circuit from the ignition coil to the battery, we can remove the wire connecting the ignition switchumage to the ignition coil and put it in the car. . If there is a scratch on the body

or chassis, if there is strong sparking, it means the circuit is normal; If there is no spark, the circuit is open.

Indirect grounding involves using a certain load of

car electrical appliances

to generate weak sparks to determine whether the line or the load is defective. For example, ground the circuit breaker lead wire of the traditional ignition system (the circuit goes through the primary winding of the ignition coil if there is one). If there is sparking, this means that this line is normal; If there is no spark, the circuit is open.

It should especially be noted that the fire test method cannot be applied to

electronic circuits

cars.

7) Incen test methodhigh voltage die

Perform a ground fire 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 from the ignition coil or spark plug, align it with the spark plug or the cylinder head, etc., with a distance of about 5mm, then turn on the start switch and run the engine, look at its bypass situation. If the sparks are strong, sky blue, and the flashover noise is loud, it means that the ignition system is operating normally

; otherwise, it means the ignition system is not working properly.

What is the operating principle of a relay? It involves attracting and closing when the power is on and releasing when the power is off. Electromagnetic relays are generally used in attomobiles.

Electromagnetic relays generally consist of an iron core, a coil,

armature

and contacts

p>

The electromagnetic force

overcomes the pulling force of the return spring and attracts the iron core to the iron core under the action of attraction , thus causing the moving contact and

the static contact of the armature

(

Normally open contact

) engages . When the coil is de-energized, the electromagnetic attraction also disappears and the armature will return to its original position under the spring reaction force, which will cause the moving contact to attract the original static contact (normally closed contact ). Of thisway, it is attracted and released to achieve the objective of conduction and breaking in the circuit. For the "normally open and normally closed" contacts of the relay, they can be distinguished as follows: the static contact in the disconnected state when the relay coil is not energized is called "normally open contact"; the state is called It is a "normally closed contact".

The causes of automobile circuit failures are: 1. The bulb is burnt out or is not bright enough. Many car owners replace it with a higher wattage bulb; The thickness of the wire is designed according to the power and current of the electrical appliance. If the power of the bulb increases and the wire is still the original wiring harness, the wire will become hot and hard after long-term operation, and the current will increase, which can easily cause a short circuit and a short-circuit accidentuit. 2 Line failure; including poor contact, loose wiring, moisture, corrosion, etc. resulting in poor insulation, resulting in short circuit, open circuit, bypass grounding, etc. 3. Component failure; General electronic components are very sensitive to overcurrent voltage and temperature. For example, the PN junction of a transistor is prone to overvoltage breakdown, and the leakage of electrolytic capacitors also increases when the temperature is high. SCR components are sensitive to overcurrent, etc. There are breakdowns caused by voltage overcurrent or overheating, which are divided into open circuits, short circuits, etc. Overcurrent voltage failures caused by circuit faults are unrecoverable. 4. Component aging performance decreases: the old electrical and electronic components of the automobile circuit system are lost,the ignition efficiency is not high and the throttle is not smooth., lack of power, increased fuel consumption, etc. There are many reasons why the overall mechanics of the car cannot be fully exercised, such as the capacity of the capacitor is reduced, the insulation resistance is reduced, the leakage of the transistor is increased, and the resistance value changes . The resistance of the adjustable resistor cannot change continuously, the relay contacts are damaged, etc. Relay components due to insulation aging, contact jitter, coil burnout, short circuit, and failure to set initializing action current. Automotive power protectors protect cars. Many automotive electronic circuits are integrated and combined, based on performance requirements or technical protection factors. Using embaNon-detachable lugs, maintenance and inspection are relatively more complicated than mechanical systems. If there is a problem with the circuit, please contact a professional technician. New cars come with various maintenance services.