I. Components of the Car Starting System
Car Ignition Switch
The car ignition switch freely turns the main circuit of the ignition coil on or off. After inserting the key into the ignition switch, pause for about 1-2 seconds in each position. You should hear the sound of electrical equipment being energized before moving to the next position.
Car Starter Relay
The starter motor requires a relatively large current to operate, and the car starter relay controls this current. It mainly controls the current in the high-voltage circuit by controlling the current in the low-voltage circuit, acting as a current switch. The starter relay is one of the components of the starting system. In a car, its main function is to use a small current to control a large current to start the motor, thereby driving the magneto rotor inside the alternator, sending an ignition pulse signal to the igniter, generating an electric spark, igniting the air-fuel mixture in the cylinder, and producing power.
Car Starter Motor
The starter motor converts electrical energy from the battery into mechanical energy, driving the engine flywheel to start the engine. Before the engine can run on its own, it must be rotated by external force. The process of the engine transitioning from a stationary state to a self-starting state with the help of external force is called engine starting.
Car Batteries and Car Jump Starters
A car battery is a device that converts chemical energy into electrical energy. It is a DC power source, and its functions include:
(1) Providing a strong starting current (approximately 10A) to the starter motor when starting the engine.
(2) Assisting the alternator in supplying power to electrical equipment when the alternator is overloaded.
(3) Supplying power to electrical equipment when the engine is idling.
(4) The battery is also a large-capacity capacitor, protecting the car’s electrical equipment.
(5) When the alternator’s terminal voltage is higher than the lead-acid battery’s electromotive force, it converts some electrical energy into chemical energy for storage, i.e., charging.
In some cases, a car jump starter can provide starting power for a dead battery, helping to start the car.
Car Alternator
The car alternator is the main power source for a car. Its function is to supply power to all electrical equipment (except the starter motor) while the engine is running normally, and to charge the battery simultaneously.
Car Fuse
A car fuse is a current fuse. When the circuit current exceeds twice the fuse’s rated current, it will melt within seconds, providing circuit protection. They are commonly used for overcurrent protection in automotive circuits and also in industrial equipment.
II. Troubleshooting Automotive Starting System
Causes
Cause 1: Battery Power Supply System Problems
For example, insufficient battery power, damaged starter fuse or relay, loose or oxidized starter cable or battery terminals, etc.
Cause 2: Starter Relay Failure
For example, short circuit in starter relay inductor coil, open circuit or grounding of starter relay inductor coil, burnt contacts or excessive gaps, etc.
Cause 3: Starter Motor Failure
For example, malfunction of the starter motor, transmission mechanism, or regulating device, etc.
Cause 4: Starter Switch Failure
Faulty starter gear.
Test Methods
Test Method 1: Battery Test
When encountering problems such as no horn, dim instrument lights, slow power window operation, dim headlights, and flashing anti-start indicator light (on some models), check if the battery terminals are oxidized or have poor contact, check if the battery grounding is faulty, and ensure that the starter motor’s starting voltage is greater than 9.6V.
Test Method 2: Starter Motor Test
Short-circuit the starter motor’s main power connector to the starter motor terminals. If the starter motor does not work, it indicates a fault in the starter motor’s solenoid switch, requiring disassembly and repair.
Test Method 3: Ignition switch and related wiring
Test Method 4: Starting relay and starting fuse testing to determine the location of the fault.