GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Radio/Audio System Check performed?

--

Go to Step 2

Go to Radio/Audio System Check

2

Do the left rear speaker(s) operate with good sound quality?

--

Go to Step 14

Go to Step 3

3

  1. Disconnect the C2 connector at the radio.
  2. Connect a digital multimeter J 39200 set on the voltage scale between the C2 connector, cavity 20 for CKT 199 (BRN), and ground.
  3. Place the ignition switch in the RUN position.

Is voltage present?

--

Go to Step 25

Go to Step 4

4

Connect a J 39200 set on the voltage scale between the C2 connector, cavity 19 for CKT 116 (YEL), and ground.

Is voltage present?

--

Go to Step 26

Go to Step 5

5

  1. Place the ignition switch in the OFF position.
  2. Connect a J 39200 set on the ohms scale between the C2 connector, cavity 20 for CKT 199 (BRN), and ground.

Is continuity present?

--

Go to Step 27

Go to Step 6

6

Connect a J 39200 set on the ohms scale between the C2 connector, cavity 19 for CKT 116 (YEL), and ground.

Is continuity present?

--

Go to Step 28

Go to Step 7

7

Connect a J 39200 set on the ohms scale between the C2 connector, cavity 20 and cavity 16.

Is the resistance within the specified range?

4-15 ohms

Go to Step 29

Go to Step 8

8

  1. Disconnect the left rear overhead radio speaker connector, and (if equipped) the left rear door radio speaker 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 30

9

  1. Connect a J 39200 set on the ohms scale between the left rear overhead radio speaker connector, cavity A and the C2 connector, cavity 19 for CKT 116 (YEL).
  2. Repeat step on left rear door speaker connector if equipped.

Is continuity present?

--

Go to Step 10

Go to Step 31

10

  1. Connect a J 39200 set on the ohms scale between the left rear overhead radio speaker connector, cavity B and the C2 connector, cavity 20 for CKT 199 (BRN).
  2. Repeat step on left rear door speaker connector if equipped.

Is continuity present?

--

Go to Step 11

Go to Step 32

11

  1. Connect a J 39200 set on the ohms scale between the left rear overhead radio speaker pins A and B.
  2. Repeat step on left rear door speaker if equipped.

Is the resistance within the specified range?

4-15 ohms

Go to Step 12

Go to Step 33

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 Radio/Audio System Check

Go to Step 13

13

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

Does sound quality improve?

--

Go to Step 33

Go to Step 29

14

  1. Disconnect the C2 connector at the radio.
  2. Connect a digital multimeter J 39200 set on the voltage scale between the C2 connector, cavity 18 for CKT 46 (DK BLU), and ground.
  3. Place the ignition switch in the RUN position.

Is voltage present?

--

Go to Step 34

Go to Step 15

15

Connect a J 39200 set on the voltage scale between the C2 connector, cavity 17 for CKT 115 (LT BLU), and ground.

Is voltage present?

--

Go to Step 35

Go to Step 16

16

  1. Place the ignition switch in the OFF position.
  2. Connect a J 39200 set on the ohms scale between the C2 connector, cavity 18 for CKT 46 (DK BLU), and ground.

Is continuity present?

--

Go to Step 36

Go to Step 17

17

Connect a J 39200 set on the ohms scale between the C2 connector, cavity 17 for CKT 115 (LT BLU), and ground.

Is continuity present?

--

Go to Step 37

Go to Step 18

18

Connect a J 39200 set on the ohms scale between the C2 connector, cavity 18 and cavity 17.

Is the resistance within the specified range?

4-15 ohms

Go to Step 29

Go to Step 19

19

  1. Disconnect the right rear overhead radio speaker connector, and (if equipped) the right rear door radio speaker connector.
  2. Inspect the connector(s) for damage, corrosion or loose fit.

Is each connector in good condition?

--

Go to Step 20

Go to Step 30

20

  1. Connect a J 39200 set on the ohms scale between the right rear overhead radio speaker connector, cavity A and the C2 connector, cavity 17 for CKT 115 (LT BLU).
  2. Repeat step on right rear door speaker connector if equipped.

Is continuity present?

--

Go to Step 21

Go to Step 38

21

  1. Connect a J 39200 set on the ohms scale between the right rear overhead radio speaker connector, cavity B and the C2 connector, cavity 18 for CKT 46 (DK BLU).
  2. Repeat step on right rear door speaker connector if equipped.

Is continuity present?

--

Go to Step 22

Go to Step 39

22

  1. Connect a J 39200 set on the ohms scale between the right rear overhead radio speaker pins A and B.
  2. Repeat step on right rear door speaker connector if equipped.

Is the resistance within the specified range?

4-15 ohms

Go to Step 23

Go to Step 33

23

  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 Radio/Audio System Check

Go to Step 24

24

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

Does sound quality improve?

--

Go to Step 33

Go to Step 29

25

Repair the short to voltage in CKT 199 (BRN).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

26

Repair the short to voltage in CKT 116 (YEL).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

27

Repair the short to ground in CKT 199 (BRN).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

28

Repair the short to ground in CKT 116 (YEL).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

29

  1. Remove and replace radio.
  2. Refer to Radio Replacement .

  3. Send faulty radio in for repair.

Is repair complete?

--

Go to Radio/Audio System Check

--

30

Repair damaged connector(s).

Refer to Connector Repairs .

Is repair complete?

--

Go to Radio/Audio System Check

--

31

Repair the open in CKT 116 (YEL).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

32

Repair the open in CKT 199 (BRN).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

33

Replace the rear overhead speaker or rear door speaker.

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

Is the repair complete?

--

Go to Radio/Audio System Check

--

34

Repair the short to voltage in CKT 46 (DK BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

35

Repair the short to voltage in CKT 115 (LT BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

36

Repair the short to ground in CKT 46 (DK BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

37

Repair the short to ground in CKT 115 (LT BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

38

Repair the open in CKT 115 (LT BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--

39

Repair the open in CKT 46 (DK BLU).

Refer to Wiring Repairs .

Is the repair complete?

--

Go to Radio/Audio System Check

--