Antenna: Testing and Inspection

Disconnect the antenna from the extension cable and plug in a test antenna. Ground the antenna to the vehicle chassis. Keep hands off of the antenna. Test radio reception in an area away from electrical interference such as tall buildings, metal structures, power lines, fluorescent lighting, and power tools. Tune to high and low ends of the dial on both AM and FM, checking weak and strong station reception. If reception is okay, the problem exists with the antenna and/or its lead-in cable. If reception is still poor, refer to "Diagnosis" of Audio Systems. Testing and Inspection

Testing for Good Ground of Antenna Mounting and Connections
Poor grounding at the antenna mounting or any connection in the antenna/lead-in system can result in seriously reduced radio performance. A poor ground can be a reason for excess ignition noise on AM or erratic audio. Also, make sure lead-in connectors are free of dirt and corrosion, and are tightly fastened.

Possible ground loss or high-resistance ground points are:
^ Antenna upper mounting (loose screws, paint over- spray, etc.).
^ Lead-in cable connector at antenna (loose or internally corroded).
^ Lead-in cable connector at radio (loose or internally corroded).
^ Quick connect connector (corroded).
^ Missing ground lead.

Lead-In Cable Diagnosis:

Usually, a broken center conductor of the lead-in cable will result in no AM and weak FM. In case of continued reception or noise complaints, always check the lead-in with an ohmmeter.

When checking resistance, wiggle the lead-in tip and cable. If the readings shown in the accompanying table are not obtained, some portion of the lead-in is intermittent. Replace the lead-in.