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.


Up next in How to Make Simple Car Repairs (13 videos)

Taking your car to the shop is expensive. Save a bundle by learning how to make some automobile fixes yourself with these tutorials..

You Will Need

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


  1. 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.

  2. 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.

  3. Test the connections with a multimeter set to measure volts.

  4. Step 3

    Inspect the amp

    Inspect the amplifier for loose hardware, screws, or nuts.

  5. Step 4

    Reconnect the other wires

    Reconnect the speaker wires and RCA cables.

  6. Keep the speaker wires from touching the vehicle as this can cause a motorboat effect.

  7. Step 5

    Replace transistors

    Remove and check any transistors that read zero ohms. Replace the transistor if it is defective.

  8. 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.

  9. Add external PC cooling fans to cool down the amplifier.

  10. 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.

  11. 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.

  12. Step 9

    Take it to a repair shop

    Take the amplifier to a repair shop if none of these fixes work.

  13. In 1930, Paul Galvin and crew of the company that would eventually become Motorola, built and installed one of the first car radios.