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 J 39916-A  .
  • Inspect the speaker connections to ensure they are clean and tight. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
  • 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 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.