Metra Line Output Converter Wiring Diagram: A Comprehensive Guide

Hello and welcome to our detailed guide on the wiring diagram for Metra Line Output Converter. In this article, we will provide you with all the necessary information to understand and correctly install the converter in your vehicle. Whether you are a car audio enthusiast or a professional installer, this guide will help you make the most out of your audio system.

1. What is a Metra Line Output Converter?

A Metra Line Output Converter, also known as LOC, is a device used to convert speaker-level signals to pre-amp level signals. It allows you to connect an aftermarket amplifier or audio processor to a factory or aftermarket head unit that lacks RCA outputs. By using an LOC, you can ensure a clean and high-quality audio signal for your amplifier.

2. Wiring Diagram

Below is a detailed wiring diagram for a Metra Line Output Converter:

Wire Color Function
Red 12V Power
Black Ground
Blue Remote Turn-On
White Left Front Speaker (+)
White/Black Left Front Speaker (-)
Gray Right Front Speaker (+)
Gray/Black Right Front Speaker (-)
Green Left Rear Speaker (+)
Green/Black Left Rear Speaker (-)
Purple Right Rear Speaker (+)
Purple/Black Right Rear Speaker (-)

Please note that the wire colors may vary depending on your specific vehicle and the model of the Metra Line Output Converter you are using. Always refer to the converter’s user manual for the correct wiring instructions.

3. Installation Process

Follow these steps to install a Metra Line Output Converter:

  1. Disconnect the negative terminal of your vehicle’s battery to prevent any electrical issues.
  2. Locate the factory head unit and remove it according to the manufacturer’s instructions.
  3. Identify the speaker wires coming from the head unit. Use a wiring diagram or a multimeter to determine the polarity of each wire.
  4. Connect the speaker-level output wires from the head unit to the corresponding input wires of the Metra Line Output Converter.
  5. Connect the RCA cables from the output side of the converter to the RCA inputs of your amplifier or audio processor.
  6. Connect the power, ground, and remote turn-on wires of the converter to their respective connections.
  7. Reconnect the negative terminal of the vehicle’s battery.
  8. Test the audio system to ensure everything is working correctly.

It is recommended to consult a professional installer or refer to the user manual of your specific Metra Line Output Converter for detailed installation instructions.

4. Advantages of Using a Metra Line Output Converter

Using a Metra Line Output Converter offers several advantages:

  • Compatibility: The converter allows you to connect aftermarket amplifiers or audio processors to factory or aftermarket head units without RCA outputs.
  • Enhanced Sound Quality: By converting speaker-level signals to pre-amp level signals, the converter ensures a cleaner and distortion-free audio signal.
  • Flexibility: You can easily upgrade your vehicle’s audio system without the need to replace the entire head unit.
  • Easy Installation: With the correct wiring diagram and basic knowledge, you can install the converter yourself.

5. Limitations and Alternatives

While Metra Line Output Converters are widely used and highly effective, they do have some limitations. One limitation is that they may introduce a slight delay in the audio signal, which can be noticeable in certain setups. Additionally, some converters may not provide the same level of signal clarity as high-end audio processors.

As an alternative, you can consider using a dedicated audio processor or a head unit with built-in RCA outputs. These options may offer more advanced features and better signal processing capabilities, but they can also be more expensive.


In summary, a Metra Line Output Converter is a valuable tool for integrating aftermarket amplifiers or audio processors into your vehicle’s audio system. By following the wiring diagram and installation process, you can achieve a clean and high-quality audio signal. While the converter has its limitations, it provides an affordable and convenient solution for upgrading your car audio system. Consider your specific needs and budget when choosing between a Metra Line Output Converter and alternative options.