GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Malibu 🢒 Power and Signal Distribution 🢒 Wiring Systems and Power Management 🢒 Radio Poor Reception

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • 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

Diagnostic Aids

Note: Radio systems with the antenna(s) in the glass are subject to possible interference when an aftermarket window tint is applied.

Poor AM and FM radio reception is dependent on multiple influences, some of which may not be vehicle related. Areas which have high RF traffic or block the signal path may cause a degradation in radio reception. Radio reception may also be influenced by items within the vehicle, but not part of the radio system. Such examples are aftermarket electrical accessories or other items which may generated noise in the vehicle electrical system.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification
  1. Inspect the antenna for physical damage.
    2. ⇒If damage is found, repair or replace as necessary
  2. Radio ON, tune to several known FM, AM, and XM (if equipped) stations, and play a known good CD.
    3. ⇒If audio output is poor from all sources, refer to Speakers Inoperative - One or More.

Circuit/System Testing

Note: For steps 5-8, perform the tests on each of the disconnected coax cables.

Rear Glass Antenna Testing

  1. Inspect the radio antenna module grounding surfaces and the mounting hardware for any corrosion that may cause a poor ground.
    2. ⇒If corrosion is noted, clean the grounding surfaces or 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.
    4. ⇒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. Disconnect both coax cables from the radio and the radio antenna module.
  5. Test for infinite resistance between the antenna coax center terminal and ground.
    6. ⇒If less than the specified value, replace the antenna coax.
  6. Test for less than 5 ohms on the antenna coax center terminal from end to end.
    7. ⇒If greater than the specified range, replace the antenna coax.
  7. Test for less than 5 ohms on the antenna coax outer shield from end to end.
    8. ⇒If greater than the specified range, replace the antenna coax.
  8. Test for infinite resistance between the coax center terminal and the outer shield.
    9. ⇒If less than the specified value, replace the antenna coax.
  9. Radio ON, verify the radio reception has improved.
    10. ⇒If there is still poor reception, replace the antenna module.
  10. If all circuits test normal, replace the radio.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Radio Antenna Module Replacement
    •  Rear Window Replacement
    •  Control Module References for Radio replacement, setup, and programming