GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the radio/audio system description and operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms

2

Verify the fault is present.

Does the system operate normally

--

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

Go to Step 3

3

  1. Disconnect the C1 connector at the radio.
  2. Connect a J 39200 digital multimeter set on the voltage scale between the C1 connector, cavity 2 for CKT 201 (TAN), and ground.
  3. Place the ignition switch in the RUN position.

Is voltage present?

--

Go to Step 14

Go to Step 4

4

Connect a J 39200 digital multimeter set on the voltage scale between the radio C1 connector, cavity 1 for CKT 118 (GRY), and ground.

Is voltage present?

--

Go to Step 15

Go to Step 5

5

  1. Place the ignition switch in the OFF position.
  2. Connect a J 39200 digital multimeter set on the ohms scale between the radio C1 connector, cavity 2 for CKT 201 (TAN), and ground.

Is continuity present?

--

Go to Step 16

Go to Step 6

6

Connect a J 39200 digital multimeter set on the ohms scale between the radio C1 connector, cavity 1 for CKT 118 (GRY), and ground.

Is continuity present?

--

Go to Step 17

Go to Step 7

7

Connect a J 39200 digital multimeter set on the ohms scale between the radio C1 connector, cavity 2 and cavity 1.

Is the resistance within the specified range?

4-15 ohms

Go to Step 18

Go to Step 8

8

  1. Disconnect the left front door radio speaker connector, and (if equipped) the left front door radio speaker tweeter connector.
  2. Inspect the connector(s) for damage, corrosion or loose fit.

Is each connector in good condition?

--

Go to Step 9

Go to Step 19

9

  1. Connect a J 39200 digital multimeter set on the ohms scale between the left front door radio speaker connector, cavity A and the radio C1 connector, cavity 1 for CKT 118 (GRY).
  2. Repeat this step on the left front door radio speaker tweeter connector if equipped.

Is continuity present?

--

Go to Step 10

Go to Step 20

10

  1. Connect a J 39200 digital multimeter set on the ohms scale between the left front door radio speaker connector, cavity A and the radio C1 connector, cavity 2 for CKT 201 (TAN).
  2. Repeat this step on tweeter connector if equipped.

Is continuity present?

--

Go to Step 11

Go to Step 21

11

  1. Connect a J 39200 digital multimeter set on the ohms scale between the left front door radio speaker pins A and B.
  2. Repeat this step on the left front door radio speaker tweeter if equipped.

Is the resistance within the specified range?

4-15 ohms

Go to Step 12

Go to Step 22

12

  1. Reconnect all connectors.
  2. Place ignition switch in the RUN position.
  3. Tune the radio to a strong, clear station.

Do the speaker(s) have good sound quality?

--

Go to Step 23

Go to Step 13

13

Substitute a known good speaker for the speaker with poor sound quality.

Does sound quality improve?

--

Go to Step 22

Go to Step 18

14

Repair the short to voltage in CKT 201 (TAN).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

15

Repair the short to voltage in CKT 118 (GRY).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

16

Repair the short to ground in CKT 201 (TAN).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

17

Repair the short to ground in CKT 118 (GRY).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

18

  1. Remove and replace radio, Refer to Radio Replacement .
  2. Send faulty radio in for repair.

Is repair complete?

--

Go to Step 23

--

19

Repair damaged connector(s).

Refer to Connector Repairs in Wiring Systems.

Is repair complete?

--

Go to Step 23

--

20

Repair the open in CKT 118 (GRY).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

21

Repair the open in CKT 201 (TAN).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 23

--

22

Replace the front door speaker or tweeter.

Refer to Radio Front Side Door Speaker Replacement or Radio Front Speaker Replacement .

Is the repair complete?

--

Go to Step 23

--

23

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3