1. Introdución
This manual provides instructions for the Metra 70-9003 Radio Wiring Harness. This harness is designed to simplify the installation of an aftermarket radio into select Audi, BMW, and VW vehicles manufactured from 2002 onwards. It eliminates the need for cutting factory wiring, ensuring a clean and straightforward connection.
2. Contido do paquete
- Metra 70-9003 Wire Harness
- Manual de instrucións

Image: The Metra 70-9003 Radio Wiring Harness as it appears in its retail packaging, showing the product label and part number.
3. Especificacións
| Marca | Metra |
| Número de modelo | 70-9003 |
| Material | Polyvinyl Chloride (PVC), Polyethylene (PE) |
| Dimensións do artigo (L x W x H) | 7.75 x 4.5 x 2 polgadas |
| Peso do elemento | 0.8 onzas (22.68 g) |
| Tipo de conector | Enchufe |
| Usos recomendados | Substitución de radio |
| Diámetro do fío | 18 Mils |
| Compatibilidade | Audi/BMW/VW 2002-Up (Confirm with Metra Vehicle Fit Guide) |
4. Instrucións de instalación
4.1 Xeralview
The Metra 70-9003 harness is designed for direct plug-and-play integration with your vehicle's factory radio connectors. The color-coded wires on the aftermarket radio side simplify connections, eliminating the need for cutting the vehicle's original wiring.
4.2 Antes de comezar
- Ensure your vehicle is compatible with the Metra 70-9003 harness. Refer to the Metra Electronics Vehicle Fit Guide or contact Metra tech support for confirmation.
- Disconnect the vehicle's negative battery terminal to prevent electrical shorts during installation.
- Gather necessary tools, which may include wire strippers, crimpers, electrical tape, and a multimeter.
4.3 Conexións de cableado
Match the color-coded wires of the Metra 70-9003 harness to the corresponding wires of your aftermarket radio's harness. Common wire functions are listed below:
- amarelo: 12V Constant Power
- Vermello: 12V Accessory Power (Switched)
- Negro: Terra
- Azul: Antena de alimentación / AmpAcendido remoto do lifier
- Laranxa: Iluminación
- Fíos dos altofalantes: (Green, Purple, Gray, White - solid for positive, striped for negative)
Secure all connections using crimp connectors or solder, and insulate them with electrical tape or heat shrink tubing to prevent short circuits.

Image: The Metra 70-9003 Radio Wiring Harness, displaying its vehicle-specific connector and the color-coded wires for aftermarket radio integration.
4.4 Conexión ao vehículo
Plug the vehicle-specific connector of the Metra 70-9003 harness into the factory radio harness located in your dashboard. Then, connect the aftermarket radio's harness (which is now wired to the Metra harness) to the new radio unit.
4.5 Testing and Reassembly
- Volva conectar o terminal negativo da batería do vehículo.
- Turn on the vehicle and test the aftermarket radio's functions, including power, audio output (all speakers), balance, fade, and illumination.
- Se todas as funcións funcionan correctamente, volva montar con coidado os compoñentes do taboleiro.
5. Instrucións de funcionamento
The Metra 70-9003 is a passive wiring harness that facilitates the electrical connection of an aftermarket radio. Its operation is entirely dependent on the functionality of the connected aftermarket radio. Refer to your aftermarket radio's instruction manual for specific operating procedures and features.
6. Mantemento
The Metra 70-9003 wiring harness requires no regular maintenance. To ensure continued performance, periodically check that all connections remain secure and are free from moisture, corrosion, or physical damage. Avoid pulling on the wires or connectors forcefully.
7 Solución de problemas
7.1 No Power to Radio
- Check the vehicle's fuse box for blown fuses related to the radio or accessory power.
- Verify the 12V constant (Yellow) and 12V accessory (Red) wires are correctly connected and receiving power using a multimeter.
- Asegúrate de que a batería do vehículo estea completamente cargada e conectada correctamente.
7.2 Sen son dos altofalantes
- Confirm all speaker wires (Green, Purple, Gray, White - solid for positive, striped for negative) are correctly matched and connected to the aftermarket radio.
- Check the aftermarket radio's settings for proper balance and fade.
- Se un externo amplifier is used, ensure the remote turn-on wire (Blue) is connected and the ampO vivificador está a recibir enerxía.
7.3 Radio Not Turning Off with Ignition
- Verify the 12V accessory (Red) wire is connected to a switched power source that turns off with the vehicle's ignition.
7.4 Cuestións xerais
- Double-check all wiring connections for looseness or incorrect pairing.
- Consult the aftermarket radio's manual for specific troubleshooting steps.
- For further assistance, contact Metra tech support.
8. Garantía e soporte
8.1 Información da garantía
The Metra 70-9003 Radio Wiring Harness comes with a 1-year limited warranty. Please retain your proof of purchase for all warranty claims.
8.2 Soporte técnico
Metra provides technical support 7 days a week for installation assistance. For contact information, please refer to the product packaging or visit Metra's official websitio.





