Car Radio Repair

Radios have been installed in cars since 1929. This Fix-It Guide on car radio repair tells how a car radio works, what often goes wrong, how to identify a car radio problem, and what parts and tools you will need to fix it. It then gives instructions for how to diagnose a clicking noise on your car radio, replace an external car antenna, remove a car radio, and clean electronic components. As they get more complex, there are fewer things that you, the car owner, can do to repair them. Even so, you still can still perform some auto radio repairs and you can replace the radio with a new one if needed.

Car Radio Repair

A car radio typically has only two external wires, one from the power source and one from the antenna.

How Does a Car Radio Work?

A car radio receiver uses an antenna to gather audio signals which it then amplifies and feeds to speakers for your enjoyment. The radio signals are amplitude modulated (AM) or frequency modulated (FM). The units often include other entertainment components, similar in design and repair to battery-operated miniature component systems, so refer to the Portable Stereo Fix-It Guide for more information on them.

What Can Go Wrong with a Car Radio?

As with other portable stereo devices, a car radio/tape/CD unit is vulnerable to mechanical problems caused by dirt and moisture. Keep the system clean and dry to minimize problems and repairs. The two most common problems are static noise and a faulty antenna.


Anti-theft devices in modern cars require that a code, stored in memory, be automatically input before the radio will operate. Knowing this, a thief may not steal radio because it won’t operate without the code. That’s the theory, anyway. Unfortunately, the code is stored only as long as your car’s battery works. Once it dies or drops below operating level the code is gone! So make sure you know the radio’s code–just in case the battery goes dead or is disconnected for even a minute (to replace the battery). Write it on the car key or in an obscure location in the owner’s manual, somewhere a thief wouldn’t be able, or think, to look. Someday you’ll thank us!

How Can I Identify a Car Radio Problem?

  • If the radio won’t work, make sure the car battery is fully charged. Also look under the dashboard for any wires that may have become unplugged.
  • If the sound is fuzzy, disassemble the unit and locate the volume control; spray electrical contact cleaner into the control and rotate or slide the control several times to lubricate the mechanism. Replace a damaged or broken antenna (see below).
  • If the radio signal crackles, check the antenna for a tight connection. Check the battery ground connection to make sure it is tight. Also, find and replace the noise-suppression filter on or near the alternator. You’ll need the car owner’s manual, a service manual, or a helpful auto parts clerk to find and replace it.

Fix-It Tip

Remember to clean the your car’s cassette deck and CD player at least twice a year, depending on how much you use them. Use a cassette tape cleaner or CD cleaner kit as recommended by the manufacturer.

What Do I Need for Car Radio Repair?

Most modern radios are built on printed circuit boards that can’t be repaired by anyone but trained technicians. However, there still are tests you can perform and parts you can replace. Check your local auto parts supplier or electronics supplier for parts and tools. Here’s what you’ll need:

  • Screwdrivers
  • Wrenches
  • Electronic contact cleaner
  • Denatured alcohol
  • Soldering iron and solder

What Are the Steps to Car Radio Repair?

Diagnose clicking noise on your car radio:

  1. If the sound is a high-pitched whine that gets higher as the engine speeds up, the cause is probably a defective noise-suppression filter. Buy an exact-replacement unit from an auto parts store and make sure it has installation instructions included.
  2. If the sound is a ticking that doesn’t get higher pitched but does become more frequent as the engine speeds up, it’s probably defective spark plug wires or a defective ignition coil capacitor. Purchase the replacement parts from an auto parts store that can advise you on installation.

Replace an external car radio antenna:

  1. Loosen the antenna mounting nut on the car fender and remove the antenna. If there is no mounting nut, you may need to access it from the underside of the fender. In some cases, you will need a special tool to remove the nut.
  2. Follow the manufacturer’s instructions for installing the replacement antenna.

Replace a built-in car radio antenna:

You can’t. Many automotive antennas are built into the frame or body of the car. To determine if your car’s antenna is replaceable, check the owner’s manual or ask an auto parts clerk.

Remove a car radio:

There are many models and installations, so this is a general discussion. Car radios typically are held in place by brackets. A face plate is a decorative cover that hides the fasteners (screws and nuts) that hold the radio onto the brackets. Once removed, the radio unit will slide toward you, allowing you to unplug electrical connections to the power, the speaker, and the antenna system. Fortunately, most modern car radios are interchangeable and include installation instructions.

Clean car radio electronic components:

  1. Unplug the receiver and open the housing (see above).
  2. Use canned air to blow dust from components, including any power cords and speaker jacks.
  3. Use electrical contact cleaner or a cotton swab dipped in denatured alcohol to clean electronic components as needed.
  4. If you find broken components on a circuit board, replace the circuit board. You can use a soldering iron and electronic solder to try to repair a component before you purchase a new circuit board.