Radio Poor Reception

RADIO POOR RECEPTION

DIAGNOSTIC SYSTEM CHECK
Perform the Diagnostic System Check - Vehicle before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information. Diagnostic System Check - Vehicle

ANTENNA SYSTEM TEST

IMPORTANT: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.

1. Disconnect the negative battery cable.
2. Disconnect the antenna lead-in connector from the radio receiver.
3. Measure the resistance from the negative battery cable to the coax (outer conductor) connector.
4. The resistance measured should be 0.2 ohms or less.
5. Test the following when the resistance is greater than 0.2 ohms:
- The base of the antenna for a poor connection to body ground
- The coaxial cable interconnects for a poor connection or corrosion
- Test for an open or high resistance from the battery negative cable to the body.
6. After finding and correcting the condition, operate the system in order to verify the repair.

Perform the Antenna Checking Procedures after confirming the integrity of the antenna ground.

ANTENNA CHECKING PROCEDURES
Perform the following tests for the type of antenna on the vehicle.

MAST ANTENNAS
Unplug the antenna lead-in connector from the radio receiver and plug a test antenna into the radio. Make sure the antenna base is grounded to the vehicle chassis and keep hands off the mast.

Check the 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 antenna and/or lead-in cable. If the reception is still poor, refer to Audio System Troubleshooting Hints. Component Tests and General Diagnostics

IMPORTANT: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.

MAST ANTENNA SYSTEM

Mast Antenna System:

Refer to the table when testing the antenna and/or lead-in cable.
1. Measure the resistance from the coax center conductor to antenna mast. Probe points 2 and 7 with the ohmmeter.
2. Measure the total resistance from end to end of center conductor. Probe points 2 and 5 with the ohmmeter:
- RG-58/RG-59 type cable-Less than 0.2 ohms
- RG-62/RG-62M type cable-Less than 3.5 ohms
3. When checking the resistance, cautiously wiggle the lead-in tip and cable.
4. Replace the antenna and/or lead-in cable when the above readings are not obtained.

POWER TYPE ANTENNAS
The following chart and diagram show ohmmeter readings which should be obtained.

IMPORTANT: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.

POWER ANTENNA SYSTEM

Power Antenna System:

Refer to the table when testing the power antenna.
1. Disconnect the negative battery cable.
2. Measure the resistance at the points specified in the table.
3. With the ohmmeter probes fastened to each point, wiggle the separate mast section and antenna housing case.
4. The resistance readings specified in the table should always be obtained. Test and/or replace the following when the resistance readings are out of specification.
- Replace the antenna mast section.
- Test the ground for an open or high resistance.
5. After finding and correcting the antenna condition, make sure the antenna lead-in connector is corrosion free and properly fastened.
6. Operate the system in order to verify the repair.