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How to Fix a Car Amp

Don't let troubles with your car amplifier silence your fun. Learn how to troubleshoot your car amplifier to resume enjoying your music.


  • Step 1: Unhook speaker wiring and RCA cables Unhook all cables and wiring from the car amplifier so that only the power, ground, and remote leads are connected.
  • Step 2: Check the connections Check the connections. Make sure the amp is grounded to a bare piece of metal free from rust, and that the remote wire is hooked up and connected to the blue wire with a white strip on the head unit.
  • TIP: Test the connections with a multimeter set to measure volts.
  • Step 3: Inspect the amp Inspect the amplifier for loose hardware, screws, or nuts.
  • Step 4: Reconnect the other wires Reconnect the speaker wires and RCA cables.
  • TIP: Keep the speaker wires from touching the vehicle as this can cause a motorboat effect.
  • Step 5: Replace transistors Remove and check any transistors that read zero ohms. Replace the transistor if it is defective.
  • Step 6: Turn down the gain Turn down the gain. If the amplifier is getting hot and shutting down, the gain might be turned up too high.
  • TIP: Add external PC cooling fans to cool down the amplifier.
  • Step 7: Connect a CD player Using a headphone to RCA cable, connect a CD player to the RCA input of the amplifier to see if the amplifier has sound. If it does, the head unit's output or cable is bad.
  • Step 8: Hook up a working speaker Hook a working speaker up to the amplifier if you are not getting sound. If you get sound from the working speaker, then the speakers in your car are blown.
  • Step 9: Take it to a repair shop Take the amplifier to a repair shop if none of these fixes work.
  • FACT: In 1930, Paul Galvin and crew of the company that would eventually become Motorola, built and installed one of the first car radios.

You Will Need

  • Multimeter
  • CD player
  • Headphone to RCA cable
  • Working speaker
  • Cooling fans (optional)

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