Metra 2 Channel Line Output Converter Wiring Diagram Pdf

Diagram
Metra 2 Channel Line Output Converter Wiring Diagram Pdf

If you're upgrading your car audio system without replacing the factory head unit, you'll inevitably run into the need for a Line Output Converter (LOC). Specifically, the Metra 2-Channel LOC is a popular and reliable choice. This article provides a detailed explanation of the Metra 2-Channel LOC wiring diagram. Understanding this diagram is crucial for successful installation, troubleshooting, and even deeper learning about car audio systems. Whether you're a seasoned modder or a mechanically inclined car owner, this guide will demystify the wiring process.

Purpose of the Wiring Diagram

The Metra 2-Channel LOC wiring diagram serves as a visual guide for connecting the LOC to your car's existing speaker wires and then to your aftermarket amplifier. The diagram ensures you connect the correct wires to the correct terminals, preventing damage to your audio equipment and your car's electrical system. It also helps in:

  • Initial Installation: Properly connecting the LOC when first installing it.
  • Troubleshooting: Identifying wiring errors that might be causing issues like distortion, no sound, or amplifier problems.
  • Repair: Correcting damaged or disconnected wires.
  • Understanding: Providing a visual representation of how the LOC interacts with the existing system, which can enhance your overall understanding of car audio electronics.

Key Specs and Main Parts of the Metra 2-Channel LOC

Before diving into the diagram, let's understand the key specifications and components of a typical Metra 2-Channel LOC.

  • Input Channels: 2 (Left and Right). These are the channels you connect to your car's speaker wires.
  • Output Channels: 2 (Left and Right). These are the RCA outputs you connect to your amplifier.
  • Ground Loop Isolation: Many Metra LOCs offer ground loop isolation to minimize unwanted noise and interference.
  • Adjustable Gain: Some models feature adjustable gain controls (potentiometers or "pots") to fine-tune the output signal level.
  • Remote Turn-On: Some LOCs generate a remote turn-on signal for your amplifier, eliminating the need to tap into an ignition wire.

The main parts involved in the wiring, as depicted in the diagram, are:

  • LOC Unit: The Metra 2-Channel Line Output Converter itself.
  • Speaker Wires (From Head Unit): The wires coming from your car's factory radio that originally connected to the speakers.
  • RCA Cables: Cables used to connect the LOC's output to your amplifier's input.
  • Power Wire (If Applicable): Some LOCs require a 12V power source for specific features (like remote turn-on generation).
  • Ground Wire: A wire connected to a solid chassis ground in your vehicle. This is critical for proper operation and noise reduction.

Symbols in the Metra 2-Channel LOC Wiring Diagram

Understanding the symbols in the wiring diagram is paramount for accurate interpretation. Here's a breakdown of common symbols:

  • Solid Lines: Represent wires. The thickness of the line doesn't necessarily indicate wire gauge, but rather visual clarity.
  • Dashed Lines: May indicate optional connections or connections within the LOC itself (internal circuitry).
  • Colors: Colors on the lines indicate the wire color. Standard car audio wiring colors are:
    • White: Usually Left Front (+) speaker wire.
    • White/Black Stripe: Usually Left Front (-) speaker wire.
    • Gray: Usually Right Front (+) speaker wire.
    • Gray/Black Stripe: Usually Right Front (-) speaker wire.
    • Green: Usually Left Rear (+) speaker wire.
    • Green/Black Stripe: Usually Left Rear (-) speaker wire.
    • Purple: Usually Right Rear (+) speaker wire.
    • Purple/Black Stripe: Usually Right Rear (-) speaker wire.
    • Red: Usually +12V (Power).
    • Black: Usually Ground.
    • Blue: Usually Remote Turn-On.

    Note: Car manufacturers don't always follow these standards. Always verify wire polarity and function with a multimeter before making connections.

  • Squares/Rectangles: Often represent connectors or terminals on the LOC or amplifier.
  • Circles: Can represent fuses or other inline components.
  • Ground Symbol: Looks like a downward-pointing triangle, often connected to a chassis ground.
  • + Symbol: Indicates positive polarity.
  • - Symbol: Indicates negative polarity.

How the Metra 2-Channel LOC Works

The LOC's primary function is to convert the high-level speaker output from your factory head unit into a low-level RCA signal that your aftermarket amplifier can use. Factory head units typically don't have RCA outputs, so the LOC acts as an interface. Here's the basic process:

  1. Signal Input: The LOC receives the amplified speaker signal from your head unit via the speaker wires.
  2. Voltage Reduction: The LOC uses internal resistors to reduce the voltage of the speaker signal to a level compatible with RCA inputs (typically around 2-4 volts). This prevents overdriving your amplifier's input stage, which can cause distortion.
  3. Ground Loop Isolation (Optional): Some LOCs incorporate transformers or other circuitry to isolate the ground between the head unit and the amplifier. This minimizes ground loops, which can introduce noise into the audio signal.
  4. Signal Output: The LOC outputs the low-level RCA signal to your amplifier.
  5. Remote Turn-On (Optional): Some LOCs detect the presence of an audio signal on the speaker wires and generate a +12V remote turn-on signal for your amplifier. This eliminates the need to find an ignition-switched +12V source.

Real-World Use and Basic Troubleshooting

Here are some common scenarios and troubleshooting tips:

  • No Sound:
    • Check the wiring: Ensure all wires are connected to the correct terminals according to the diagram. Pay close attention to polarity (+ and -).
    • Verify the ground connection: A poor ground connection is a common culprit. Make sure the ground wire is securely attached to a clean, bare metal surface on the car's chassis.
    • Check the RCA cables: Ensure the RCA cables are securely connected to both the LOC and the amplifier. Try swapping the RCA cables to rule out a faulty cable.
    • Check the amplifier's power and ground: Verify that the amplifier is receiving power and has a good ground connection.
    • Bypass the LOC (for testing): If possible, temporarily bypass the LOC by connecting the speaker wires directly to the amplifier (if the amplifier has high-level inputs). This will help determine if the LOC is the source of the problem. Warning: be extremely careful when directly wiring speaker outputs to an amp with high level inputs. You can severely damage the amp or head unit if you connect improperly.
  • Distortion:
    • Adjust the gain: If your LOC has adjustable gain controls, try lowering the gain. Too much input signal can cause distortion.
    • Check for ground loops: Try different grounding locations to see if it reduces the distortion. A ground loop isolator might be necessary.
    • Verify speaker wire polarity: Incorrect polarity can sometimes cause distortion.
  • Noise (Hum or Hiss):
    • Check for ground loops: This is the most common cause of noise. Ensure all components share a common ground point. Try grounding the LOC near the amplifier.
    • Shielded RCA cables: Use high-quality shielded RCA cables to minimize interference.
    • Route RCA cables away from power wires: Running RCA cables near power wires can induce noise.

Safety Considerations

Working with car electrical systems can be dangerous. Here are some crucial safety precautions:

  • Disconnect the Battery: Always disconnect the negative terminal of your car battery before working on any electrical components. This will prevent accidental short circuits.
  • Fuse Protection: Ensure your amplifier and any other powered components are properly fused. Use the correct fuse rating as specified by the manufacturer.
  • Wire Gauge: Use the appropriate gauge wire for the current draw of your amplifier and other components. Undersized wire can overheat and cause a fire.
  • Proper Connections: Use proper crimping tools and connectors to ensure secure and reliable connections. Loose connections can cause voltage drops and heat buildup.
  • Avoid Sharp Edges: Route wires carefully to avoid sharp edges that could chafe the insulation and cause a short circuit. Use grommets when passing wires through metal panels.
  • Airbags: Be extremely careful when working near airbags. Consult your car's service manual for instructions on how to safely disable airbags if necessary.

Remember, if you're uncomfortable working with car electrical systems, it's always best to consult a professional installer.

We have the Metra 2-Channel Line Output Converter Wiring Diagram PDF available for download. It contains specific wiring instructions and schematics that can be invaluable during your installation process.

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