GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Body and Accessories 🢒 Entertainment 🢒 Radio Display Does Not Dim with Instrument Panel Dimmer Switch

Step

Action

Value(s)

Yes

No

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 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

Is vehicle equipped with a remote compact disc player?

--

Go to Step 4

Go to Step 5

4

Does the radio illumination dimming operate properly?

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Go to Step 8

Go to Step 5

5
  1. Disconnect the radio C1 connector.
  2. Place the headlamp switch in the PARK position.
  3. Observe that the park lamps are operating.
  4. Adjust the IP dimmer switch thumbwheel to the mid-range position.
  5. Test for voltage using a J 39200 digital multimeter, between the radio C1 connector, cavity 7 for CKT 8 (GRY) and ground.

Is voltage present?

--

Go to Step 9

Go to Step 6

6
  1. Remove fuse 14 (ILLUM) from the IP fuse block.
  2. Test for voltage between the IP fuse block, cavity E3 and ground, using a J 39200 digital multimeter.

Is voltage present?

--

Go to Step 10

Go to Step 7

7
  1. Place the headlamp switch in the OFF position.
  2. Adjust the IP dimmer switch thumbwheel to just before the detent position.
  3. Disconnect the headlamp switch connector.
  4. Test for continuity between the headlamp switch, pin E and pin H, using a J 39200 digital multimeter.

Is continuity present?

--

Go to Step 11

Go to Step 12

8
  1. Disconnect the remote compact disc player connector.
  2. Place the headlamp switch in the PARK position.
  3. Observe that the park lamps are operating.
  4. Adjust the IP dimmer switch thumbwheel to the mid-range position.
  5. Turn the radio ON.
  6. Test for voltage using a J 39200 digital multimeter, between the remote compact disc player connector, cavity 8 for CKT 8 (GRY) and ground.

Is voltage present?

--

Go to Step 13

Go to Step 14

9
  1. Replace the radio. Refer to Radio Replacement .
  2. Send defective radio in for repair.

Is the repair complete?

--

Go to Step 15

--

10

Repair the open in CKT 8 (GRY) between the IP fuse block and the radio C1 connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 15

--

11

Repair the open in CKT 44 (DK GRN) between the headlamp switch connector and the IP fuse block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 15

--

12

Replace the headlamp switch. Refer to Headlamp Switch Replacement in Lighting Systems.

Is the repair complete?

--

Go to Step 15

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13
  1. Replace the remote compact disc player. Refer to Remote Compact Disc Player Replacement .
  2. Send defective player in for repair.

Is repair complete?

--

Go to Step 15

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14

Repair the open in CKT 8 (GRY) between the radio C3 connector and the remote compact disc connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 15

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15

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3