GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 Sonoma Pickup - 4WD 🢒 Body and Accessories 🢒 Entertainment 🢒 Rear Seat Radio Controls Inoperative

Step

Action

Value(s)

Yes

No

1

Did you perform Radio/Audio System Check?

--

Go to Step 2

Go to Radio/Audio System Check

2

Is the power ON indicator inoperative only?

--

Go to Step 3

Go to Step 5

3

Test CKT 314 (PNK) at the rear seat audio module for voltage.

Is voltage present in CKT 314 (PNK)?

--

Go to Step 18

Go to Step 4

4

Repair the open in CKT 314 (PNK).

Is the repair complete?

--

Go to Radio/Audio System Check

--

5

When the PWR button is pressed to select ON, verify the that the following conditions exist:

    • Power indicator ON inoperative.
    • Rear door speakers do not mute.
    • Rear door speaker audio is at a loud unadjustable volume.

Do the conditions exist?

--

Go to Step 6

Go to Step 11

6

Test CKT 314 (PNK) for a short to ground.

Is a short to ground present in CKT 314 (PNK)?

--

Go to Step 7

Go to Intermittents and Poor Connections Diagnosis

7

Disconnect the rear seat audio module.

Is a short to ground present in CKT 314 (PNK)?

--

Go to Step 8

Go to Step 18

8

Disconnect the radio.

Is a short to ground present in CKT 314 (PNK)?

--

Go to Step 9

Go to Step 22

9

Disconnect the amplifier.

Is a short to ground present in CKT 314 (PNK)?

--

Go to Step 10

Go to Step 27

10

Repair the short to ground in CKT 314 (PNK).

Is the repair complete?

--

Go to Radio/Audio System Check

--

11

Are both channels inoperative?

--

Go to Step 13

Go to Step 12

12

Is the left channel inoperative?

--

Go to Step 25

Go to Step 26

13
  1. Turn the ignition switch to ACC position.
  2. Connect (backprobe) the J 39200 DMM to cavity M for CKT 1011 (LT GRN) of the rear seat audio module.
  3. Press and hold the PWR button.

Is voltage within the specified range?

3.1--3.3 V

Go to Step 19

Go to Step 14

14

Test CKT 1301 (DK GRN) for an open circuit.

Is an open present in CKT 1301 (DK GRN)?

--

Go to Step 15

Go to Step 16

15

Repair the open in CKT 1301(DK GRN).

Is the repair complete?

--

Go to Radio/Audio System Check

--

16

Test CKT 1050 (BLK ) for an open circuit.

Is an open present in CKT 1050 (BLK)?

--

Go to Step 17

Go to Step 18

17

Repair the open in CKT 1050 (BLK).

Is the repair complete?

--

Go to Radio/Audio System Check

--

18

Replace the rear seat audio module. Refer to Rear Seat Audio Control Replacement .

Is the replacement complete?

--

Go to Radio/Audio System Check

--

19
  1. Turn the ignition switch to the OFF position.
  2. Test CKT 1011 (LT GRN) for an open circuit.

Is an open present in CKT 1011 (LT GRN)?

--

Go to Step 20

Go to Step 21

20

Repair the open in CKT 1011 (LT GRN).

Is the repair complete?

--

Go to Radio/Audio System Check

--

21
  1. Turn the ignition switch to the ACC position.
  2. Press and release the PWR button of the rear seat audio module.
  3. Test CKT 314 (PNK) at the radio (backprobe) for voltage.

Is voltage within the specified range?

9--16 V

Go to Step 23

Go to Step 22

22

Service the radio. Refer to Radio Replacement .

Is service of the radio complete?

--

Go to Radio/Audio System Check

--

23

Test CKT 314 (PNK) at the amplifier (backprobe) for voltage.

Is voltage within the specified range?

9--16 V

Go to Step 25

Go to Step 24

24

Repair the open in CKT 314 (PNK).

Is the repair complete?

9--16 V

Go to Radio/Audio System Check

--

25

Important: The audio output signal can be identified as a fluctuating AC voltage. Measure from the channel output cavity to the channel common ground cavity.

  1. Verify that the system is ON.
  2. Test for left channel audio output at the amplifier.

Is the left channel audio output present?

100--400 mV AC

Go to Step 28

Go to Step 27

26

Important: The audio output signal can be identified as a fluctuating AC voltage. Measure from the channel output cavity to the channel common ground cavity.

  1. Verify that the system is ON.
  2. Test for right channel audio output at the amplifier.

Is the right channel audio output present?

100--400 mV AC

Go to Step 28

Go to Step 27

27
  1. Service the amplifier. Refer to Radio Speaker Amplifier Replacement .
  2. Before reinstalling the amplifier, inspect the harness for bare wire(s). Repair the harness as necessary.

Is service of the amplifier complete?

--

Go to Radio/Audio System Check

--

28

Important: The audio output signal can be identified as a fluctuating AC voltage. Measure from the channel input cavity to the channel common ground cavity.

Test for audio input to the rear seat audio module.

Is the audio signal present?

100--400 mV AC

Go to Step 18

Go to Step 29

29

Are both channels inoperative?

--

Go to Step 30

Go to Step 31

30

Repair the open in CKT 372 (BLK/WHT).

Is the repair complete

--

Go to Radio/Audio System Check

--

31

Is the right channel input inoperative?

--

Go to Step 32

Go to Step 33

32

Repair the open in CKT 368 (DK GRN/WHT).

Is the repair complete?

--

Go to Radio/Audio System Check

--

33

Repair the open in CKT 367 (BRN/WHT).

Is the repair complete?

--

Go to Radio/Audio System Check

--