Detailed Explanation of the Characteristics and Types of Automotive Wire Harnesses

Detailed Explanation of Automotive Wire Harness Characteristics and Types

As car-sharing becomes more mainstream and automobiles are increasingly prevalent as crucial means of transportation, higher performance demands are placed on automotive interior components.

This not only affects a vehicle's service life but also has a direct bearing on safety.

Automotive wires, serving as internal connectors, are used for current transmission in batteries, instruments, lights, etc.

They must be cold and high-temperature resistant – a standard inferior rubber materials simply can't meet.

Automotive wires differ from ordinary household ones.

Household wires are usually copper single-core wires with some rigidity, while automotive wires are copper multi-core flexible wires, comprising several to dozens of soft copper strands encased in plastic insulation tubes (PVC or fluoroplastic resin), making them flexible and less prone to breakage.

Given the automotive industry's unique traits, the manufacturing process of automotive wires is also more specialized.

There are two main types:

high-voltage and low-voltage wires, both crafted from quality copper multi-core flexible wires.

The conductor's cross-sectional area is chosen based on the working current.

For appliances with tiny currents, to guarantee a certain mechanical strength, the area should be no less than 0.5mm².

Since starters work briefly, to ensure they function properly and output enough power, the voltage drop caused by 100A current on the circuit must not exceed 0.1V - 0.15V, necessitating larger cross-sectional areas for relevant wires.

High-voltage automotive wires, withstanding over 15kV, have small cross-sections (due to low current), around 1.5mm², and thicker insulation layers, often using rubber insulation, fluoroplastic resin, or cotton braided with impregnated paint.

Common automotive wire models include the national standard QVR - 105, Japanese standards like AV, AVS, AVSS, AVX/AEX, German standards such as FLRY - B, FLRY - A, FLRYK - A, FLRYK - B, FLRYW - A, FLRYW - B, and American standards GTE, GPT, GXL, SXL, TWE, TWP, TXL.

The selection of automotive wires hinges on insulation level, passing current, and required mechanical strength.

For long-running electrical equipment, wires with 60% of the actual current-carrying capacity can be chosen; for short-term equipment, select ones with a capacity between 60% and 100%.

The automotive electrical system has low-voltage supply, large working current, and significant voltage loss. Excessive voltage loss can disrupt electrical equipment operation.

Now, let's look at the classification of major automotive wire harnesses:

 Main Wire Harness: Distributed across the chassis and engine compartment, with a small portion inside the compartment. It further branches into smaller harnesses like the left and right front door harnesses, rear door harness, ceiling harness, rear back door (trunk) harness, antenna harness, front and rear bumper harnesses, positive and negative cables.

Cockpit Wire Harness (Body Wire Harness): Predominantly found within the vehicle compartment.

Instrument Wire Harness: Located within the instrument panel.

Engine Wire Harness: Mounted on the engine.

Here are the functions of six common automotive wire harnesses:

 Engine Wire Harness: Connects engine components and systems, transmitting power and signals among the engine control unit, sensors, and actuators.

Body Wire Harness: Links various body equipment and systems, powering and signaling lights, instrument panels, air-conditioning, and audio systems.

Instrument Wire Harness: Connects the instrument panel to the driver's control panel, facilitating the transmission of indicator lights, instrument readings, and control signals.

Lighting Wire Harness: Connects the vehicle lighting system, sending power and signals to headlights, tail lights, and turn signals.

Front and Rear Windshield Wire Harness: Powers and signals electronic devices and sensors on windshields, such as those for wipers and rain-light sensors.

Seat Wire Harness: Connects seat electronics and sensors, enabling functions like heating, ventilation, and massage by transmitting power and signals.