GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Symptoms

2

Verify that the radio display does not dim with the IP dimmer switch.

Does the radio display dim normally with the IP dimmer switch?

--

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

Go to Step 3

3

  1. For Chevy/GMC (except Envoy) determine if the vehicle is equipped with an optional remote Tape/CD player.
  2. Determine if only the remote Tape/CD player illumination is inoperative.

Is the remote Tape/CD player illumination inoperative?

--

Go to Step 6

Go to Step 4

4

  1. Disconnect the radio.
  2. Turn the headlamp switch to the PARK position.
  3. Turn the instrument panel dimmer switch to a mid-range position.
  4. Test CKT 1220 (GRY) for voltage.

Is voltage present in CKT 1220 (GRY)?

--

Go to Step 10

Go to Step 5

5

Repair an open in CKT 1220 (GRY) between the radio and S205. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 11

--

6

  1. Disconnect the remote Tape/CD player.
  2. Turn the headlamp switch to the PARK position.
  3. Turn the instrument panel dimmer switch to a mid-range position.
  4. Test CKT 1220 (GRY) for voltage.

Is voltage present in CKT 1220 (GRY)?

5-8 V

Go to Step 7

Go to Step 8

7

Service the remote Tape/CD player. Refer to Remote CD Changer Replacement or Remote Tape Player Replacement .

Is service of the remote Tape/CD player complete?

--

Go to Step 11

--

8

Test CKT 1220 (GRY) for an open circuit.

Is an open present in CKT 1220 (GRY)?

--

Go to Step 9

Go to Step 10

9

Repair the open in CKT 1220 (GRY). Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 11

--

10

Service the radio. Refer to Radio Replacement .

Is service of the radio complete?

--

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3