How to diagnose car radio noise

Updated February 21, 2017

Noise in your car radio can come from many places inside the car and under the bonnet. The noises can be whines, clicks, rumbles or just plain old static. Is the noise on your AM radio or on the FM stereo? Can it be heard when you are playing a tape or CD? What form does it take? These are some of the many questions you can answer with a few simple checks. There are many products on the market designed to suppress noise in your car radio. Most are not needed and a do-it-yourself car audio checkup can probably locate the problem.

Check the antenna. If your car antenna is mounted on the chassis, it is out in the elements. Wind, rain, snow and sleet can cause a connection problem. Do you have a flag, flower or other object mounted on the antenna? Wind pressure on the object can cause unwanted vibrations that can loosen the antenna connection.

Try and turn the antenna to see if it is loose. With the radio playing and the engine off move the antenna slowly back and forth. If it creates static, tighten the connection.

Tune your AM radio dial slowly from the top of the dial toward the low frequencies with the engine running. AM radio is Amplitude Modulated and will pick up engine noise if the radio is poorly grounded or if new spark plug wires are needed. Make sure the ground wire on the back of the radio is tightly connected to the chassis.

Listen to the FM stereo with the car engine running. A high-pitched whine could indicate a poorly grounded alternator. A good solid ground from the alternator to the chassis is important.

Turn the radio on with the engine turned off and use the indicators and brakes. Clicking sounds could indicate a bad ground on the radio. Check fuse connections for brakes and indicators.

Solve most car audio problems by checking the integrity of the ground connections on the noise producers like spark plugs, alternator, heater and air conditioner motors in the car. Connections for all parts of your vehicle's electrical system must be good and the integrity of each one should be checked until the source of your audio noise is located.


When possible, follow the engineer's one-hand rule when working with electrical wiring. Keep one hand in your pocket when working with any wire carrying an electrical charge. This will help you avoid electrical shock.


Use caution when checking any electrical wiring. Do not run the engine in an enclosed space while doing your audio check.

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About the Author

Lon Quist wrote news and scripts for radio stations. His novel "Pennyman" was published by MtSky Press. He has a broadcasting degree from the American Institute of the Air and engineering degree from Brown Institute. Licensed by the FCC, he was a radio station chief engineer and has been a writer for 40 years.