GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Schematic Reference: Radio/Audio System Schematics

1

Did you review the Radio/Audio System Description and Operation and perform the necessary inspections?

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Go to Step 2

Go to Radio/Audio System Description and Operation

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the radio.
  3. Tune the radio to a known strong AM station, then tune to a known strong FM station.

Is the radio reception clear?

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Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Inspect for the following:

    • Radio antenna coaxial cable interconnects for corrosion and proper connection
    • Proper connection at the antenna

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

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Go to Step 12

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable.
  3. Disconnect the radio.
  4. Zero the DMM.
  5. Measure the resistance between the negative battery cable and the radio coaxial ground at the radio.

Is the resistance within the specified value?

Less than

    • 0.135 ohms 5 ft lead-ins
    • 0.160 ohms 13 ft lead-ins
    • 0.185 ohms 20 ft lead-ins

Go to Step 5

Go to Step 6

5

  1. Grasp the antenna mast.
  2. Monitor the DMM and wiggle the antenna mast.

Does the DMM display intermittent continuity?

--

Go to Step 6

Go to Step 7

6

Inspect the antenna base for a proper connection to the body ground.

Did you find and correct the condition?

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Go to Step 12

Go to Step 8

7

  1. Remove the radio antenna coaxial lead-in connector from the radio.
  2. Measure the resistance between the radio antenna coaxial lead-in, center conductor, connector and the antenna mast with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the measured resistance less than the specified values?

RG-58/ RG-59 Coax: 0.2 ohms end to end

RG-62/ RG-62M Coax: 0 .15-0.20 ohms/ft less than 3.5 ohms from end to end

Go to Step 9

Go to Step 10

8

Inspect the ground connection from the battery negative cable to the body. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Test for continuity between the antenna coaxial cable center conductor and metal case on both ends of the cable.

Did you measure continuity?

--

Go to Step 11

Go to Step 10

10

Inspect the radio antenna coaxial cable interconnects for a poor connection or corrosion. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

11

Repair or replace the radio antenna coaxial cable circuit.

Did you complete the repair or replacement?

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Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Audio System Troubleshooting Hints