In ten minutes, we’ll take you deep into the world of car audio color codes, helping you connect wiring harnesses correctly and avoid short circuits caused by incorrect connections.
The Role of Car Audio Wiring Harness
A car audio wiring harness serves as an integrated adapter. It facilitates connectivity between different brands of audio head units and the vehicle’s factory wiring harness connectors. It is essential to select the appropriate harness for both the vehicle and the audio system.
Core Functions of Car Audio Wiring Harness
Superior electrical performance is critical for ensuring audio signal clarity and stability.
- Power Transmission: Provides stable, continuous power supply to the head unit.
- Signal Transmission: Delivers audio signals with low loss and precision to each speaker.
- Control and Integration: Wires transmit control signals.
Car Audio Wiring Harness: EIA Color Standard
Below is the EIA color standard, which defines the color coding followed by aftermarket car audio wiring harnesses.
| Color | Function | Detailed Description |
| Yellow | 12V Constant Power Supply (BATTERY / B+) | Directly connect to the battery positive terminal to provide the audio head unit with a “memory” power supply for preserving settings and time. |
| Red | 12V Accessory/Ignition Power Supply (ACC) | Connected to the vehicle’s ignition switch. Only energized when the key is turned to the ACC or ON position, used to control the main unit switch. |
| Black | Grounding | The metal frame connected to the vehicle forms an electrical circuit loop. This is one of the most critical connections. |
| Blue | Electric Antenna Control Cable | When the radio function is activated, it outputs a +12V voltage to raise the electric antenna. It turns off when the radio is not in use. |
| Blue and white stripes | Power Amplifier Start/Remote Control Cable | When the audio head unit is turned on (regardless of the audio source), it outputs a +12V voltage to power up the external amplifier. |
| Orange | Lighting/Dimming Cable | Connected to the vehicle’s headlight switch circuit. When you turn on the headlights, this wire receives a signal and the main unit automatically dims the screen brightness. |
| Orange and white stripes | Dimmer Control Wire | Similar to the orange line, but sometimes used for finer brightness adjustments. |
| White | Left front speaker (+) positive terminal | |
| White/Black Stripes | Left Front Speaker (-) Negative Terminal | |
| Gray | Right front speaker (+) positive terminal | |
| Gray/Black Stripes | Right Front Speaker (-) Negative Terminal | |
| Green | Left Rear Speaker (+) Positive Terminal | |
| Green/Black Stripes | Left Rear Speaker (-) Negative Terminal | |
| Purple | Right Rear Speaker (+) Positive Terminal | |
| Purple/Black Stripes | Right Rear Speaker (-) Negative Terminal | |
| Brown | Silent | Typically used to connect to the vehicle’s phone system, automatically muting the audio system when a call comes in. |
Different audio brands may have slightly different labeling, but power cables and ground wires are universally compatible. If your audio head unit comes with a pigtail connector and uses standard color coding, be sure to consult your user manual.
Differences Between OEM and Aftermarket Wiring Harness
- OEM (Original Equipment Manufacturer) Audio Wiring Harness: This harness is factory-installed with connectors and wire colors defined by the automaker. There is virtually no standardization across different brands and models. This variation primarily stems from manufacturers prioritizing cost control when designing vehicle electrical systems.
- Aftermarket Head Unit Wiring Harness: When modifying the OEM harness during an upgrade, do not attempt to guess or connect based on EIA standards. The most reliable method is to use vehicle-specific wiring harness adapters. Advantages of dedicated adapters: They enable seamless plug-and-play connections without cutting any original wires. Installation is simple and reduces error risks: Simply match the adapter’s standard color wires to the new head unit’s corresponding colors, significantly lowering the risk of short circuits caused by wiring mistakes that could burn out the new head unit or even the vehicle’s computer.
Understanding Car Audio Wiring Diagrams
Wiring diagrams function like color-coded charts, where automakers identify OEM wire colors and connection points.
When connecting audio equipment, adapters must match wiring harness functions—not merely wire colors.
- Ground Wire: Black wire connects to a solid chassis point for grounding.
- Power Wire: Yellow (Battery) and Red (Ignition) must connect to their respective constant power or ACC power sources. Orange wire handles lighting or dimming functions.
- Speakers: Pair speaker wires by color, distinguishing positive and negative terminals for each wire.
Proper Gauge (AWG) for Audio Wiring Harness
- Power: Head units typically require 18 AWG or 16 AWG.
- Ground wire: Standard selection depends on amplifier total power (RMS) and wire length.
- Amplifier power < 400W RMS: 8 AWG
- Amplifier power 400W – 600W RMS: 4 AWG
- Amplifier power 600W – 1000W+ RMS: 2 AWG or 1/0 AWG
- Amplifier:
- Standard speakers (< 75W RMS): 16 AWG
- High-power speakers/subwoofers (> 75W RMS): 14 AWG or 12 AWG recommended.
- Remote start wire: 18 AWG is sufficient for control start functions.
Car Audio Wiring Harness Safety Guidelines
- Fuses: Install fuses on the main power line to prevent fires and other accidents caused by short circuits.
- Grounding: Connect the black wire to a solid chassis point. Clean the contact surface to ensure minimal resistance.
- Routing Path: Avoid electromagnetic interference by routing power cables and audio signal cables on opposite sides of the vehicle.
Wire Harness Connectors & Products
This guide explains the color-coding system for car audio wire harnesses. Accurate wiring diagrams are essential for flawless audio system integration. Use premium connectors and harnesses for damage-free modifications to prevent functionality failures and safety hazards.
JinHai offers a comprehensive range of wire harness kits and adapters. Components feature clear labeling and seamless compatibility with factory functions, ensuring damage-free connections that preserve your vehicle’s original value.
Contact us immediately to learn how we can meet your cable and harness requirements. Follow us on Youtube .
