Radio Poor Reception

Radio Poor Reception

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

AM and FM radio reception is dependent on the following components:

* Radio antenna - part of the rear window
* Coax cable between the radio antenna and the radio antenna module
* Radio antenna module
* Coax cable between the radio antenna module and the radio
* Radio

Circuit/System Testing

Antenna Coaxial Cable Testing

Important: For steps 2-5, perform the tests on each of the disconnected coax cables.

1. Ignition OFF, disconnect all coax cables from the radio, radio antenna module, and the antenna.
2. Test for infinite resistance between the antenna coax center terminal and ground.

• If less than the specified value, replace the antenna coax.

3. Test for less than 5 ohms on the antenna coax center terminal from end to end.

• If greater than the specified range, replace the antenna coax.

4. Test for less than 5 ohms on the antenna coax outer shield from end to end.

• If greater than the specified range, replace the antenna coax.

5. Test for infinite resistance between the coax center terminal and the outer shield.

• If less than the specified value, replace the antenna coax.

Antenna Inspection
1. Ignition OFF, disconnect the coax cable from the antenna located on the rear window.
2. Verify the coax connectors are properly secured and free of any damage.

• If damage is found, repair or replace as necessary.

3. Inspect the antenna. Verify all branches of the antenna are intact, with no scratches or other damage.

• If damage is found, repair or replace as necessary.

Radio Antenna Module Test
1. Inspect the antenna module grounding surface and mounting hardware for any corrosion that may cause a poor ground.

• If corrosion is noted, clean the grounding surfaces and hardware.

2. Ignition OFF, disconnect the harness connector at the radio antenna module.
3. Radio ON, test for B+ between the signal circuit terminal 1 and ground.

• If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.

4. If all circuits test normal, replace the antenna amplifier module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Antenna Cable Replacement
* Radio Antenna Module Replacement
* Rear Window Replacement