Preliminary Inspections

IMPORTANT: When testing the audio system for poor reception or noise, the vehicle should be outside away from metal buildings and utility lines, with the hood and rear compartment closed.

Check for any aftermarket equipment that may have been installed on the vehicle. If aftermarket equipment is found disconnect it and check if the audio noise is still present.
Inspect that the antenna connector and the antenna coaxial cable are clean and tight.
For reception concerns, first determine if the customer is within the listening area of the stations they are attempting to receive.
Stations at the lower end of the FM band are more susceptible to audio noises than stations at the higher end.
If the noise is only from one speaker check for the following before speaker replacement:
- Isolate the noise using the J39916-A CD and Cassette Diagnostic Audio Kit.
- Inspect the speaker connections to ensure they are clean and tight. Refer to TESTING FOR INTERMITTENT & POOR CONNECTIONS in WIRING SYSTEMS article.
- Inspect for a loose or incorrectly installed speaker or surrounding trim. Loose trim can cause a buzz or flutter which sounds like a malfunctioning speaker.
Ignition noise on the FM band may be an indication of an ignition system problem.
Inspect that all vehicle grounds are clean, tight and free of corrosion.
Inspect the rear defogger grid lines for large breaks or dark spots.
Inspect the connections at the radio antenna module if equipped, to ensure that they are clean and tight.
Compare the customers vehicle to another of similar model and audio system to determine if the condition is abnormal.