Always perform the Diagnostic System Check - Vehicle before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle .
Use a test mast antenna to quickly check for poor vehicle antenna operation. Unplug antenna lead-in connector from radio receiver and plug a test antenna into radio. Make sure the test antenna base is grounded to the vehicle chassis and keep hands off the mast. Check radio reception in an area away from electrical interferences. Tune to several weak and strong AM and FM stations. If the radio reception improved, the problem exists with the vehicle antenna and/or lead-in cable. If the reception is still poor, refer to Audio System Troubleshooting Hints .
Important: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.
Use the appropriate chart and diagram to test the antenna coaxial cable resistances for the antenna system on the vehicle. Refer to the table when testing the antenna and/or lead-in cable.
Ohmmeter Probes At Points
Resistance Measured In Ohms
1 and 3
Less than 0.2
1 and 4
1 and 6
1 and 2
Infinite
1 and 5
1 and 7
2 and 3
2 and 4
2 and 6
3 and 4
3 and 6
3 and 5
3 and 7
The following chart and diagram show ohmmeter readings which should be obtained.
7 and 6
5 and 4
7 and 4
Refer to the table when testing the power antenna.
Inspect the antenna connector wire at base of windshield. Make sure the wire is not pinched or broken and is fully seated into the lead-in receptacle.
Inspect dipole wires within the windshield for breaks. Use the figure and table for the mast antenna as a guide to test for continuity within the antenna coaxial cable. Repair or replace any portion of the coaxial cable that does not meet the resistance measurements. If test antenna indicates radio is OK and lead-in checks fine, the windshield may need to be replaced. A defective windshield antenna results in loss of sensitivity, particularly on AM.
Important: The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
This antenna system uses the existing rear defogger grid as an antenna. Using the defogger as an antenna requires the circuitry in the radio antenna module to decouple the RF from the DC heater current.
Perform the Antenna System Test and test the antenna coax cable prior to performing the following tests.
This antenna system uses two antennas to form a diversity system. The primary antenna is part of the rear window. The primary antenna receives both AM and FM signals. The secondary antenna is located on the passenger side of the windshield. The secondary antenna receives only FM signals. The radio antenna module processes the antenna reception signals and phase aligns them to create one strong signal.