1. Introduction
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. Package Contents
- Metra 70-9003 Wire Harness
- Instruction Manual
Image: The Metra 70-9003 Radio Wiring Harness as it appears in its retail packaging, showing the product label and part number.
3. Specifications
| Brand | Metra |
| Model Number | 70-9003 |
| Material | Polyvinyl Chloride (PVC), Polyethylene (PE) |
| Item Dimensions (L x W x H) | 7.75 x 4.5 x 2 inches |
| Item Weight | 0.8 ounces (22.68 g) |
| Connector Type | Plug-in |
| Recommended Uses | Radio Replacement |
| Wire Diameter | 18 Mils |
| Compatibility | Audi/BMW/VW 2002-Up (Confirm with Metra Vehicle Fit Guide) |
4. Installation Instructions
4.1 General Overview
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 Before You Begin
- 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 Wiring Connections
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:
- Yellow: 12V Constant Power
- Red: 12V Accessory Power (Switched)
- Black: Ground
- Blue: Power Antenna / Amplifier Remote Turn-On
- Orange: Illumination
- Speaker Wires: (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 Connecting to Vehicle
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
- Reconnect the vehicle's negative battery terminal.
- Turn on the vehicle and test the aftermarket radio's functions, including power, audio output (all speakers), balance, fade, and illumination.
- If all functions operate correctly, carefully reassemble the dashboard components.
5. Operating Instructions
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. Maintenance
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. Troubleshooting
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.
- Ensure the vehicle's battery is fully charged and properly connected.
7.2 No Sound from Speakers
- 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.
- If an external amplifier is used, ensure the remote turn-on wire (Blue) is connected and the amplifier is receiving power.
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 General Issues
- 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. Warranty & Support
8.1 Warranty Information
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 Technical Support
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 website.
