GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Lighting Systems Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Connect a scan tool to the data link connector (DLC).
  2. Select INCANDESCENT DIMMING from the instrument cluster (IPC) data list.
  3. Rotate the headlamp switch dimming control to the extreme clockwise position.

Does the scan tool value change?

--

Go to Step 3

Go to Step 4

3

  1. Rotate the headlamp switch dimming control to the extreme counter-clockwise position. Note that the value should gradually decrease as the switch is rotated.
  2. If sudden large decreases are noted, then replace the headlamp switch. Refer to Headlamp Switch Replacement in Lighting Systems.

Is the scan tool value near the specified value?

0

Go to Step 6

Go to Step 4

4

  1. Turn the ignition switch to the RUN position.
  2. Rotate the headlamp switch dimming control to the extreme counterclockwise position.
  3. Measure the voltage from the instrument cluster connector C3 cavity D13 (BLK) to ground.

Is the voltage within the specified range?

4.4-4.8 V

Go to Step 5

Go to Step 7

5

  1. Rotate the headlamp switch dimming control to the extreme clockwise position.
  2. Measure voltage from the instrument panel cluster (IPC) connector C3 cavity C10 (DK GRN) to ground.

Is the voltage within the specified range?

0.2-0.6 V

Go to Step 6

Go to Step 7

6

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the instrument cluster replacement complete?

--

Go to Step 14

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7

  1. Disconnect the headlamp switch connector C2.
  2. Disconnect the instrument cluster connector C3.
  3. Measure resistance from the headlamp switch connector C2 cavity B (DK GRN) to the instrument cluster connector C3 cavity C10 (DK GRN).

Is the resistance less than the specified value?

5 ohms

Go to Step 8

Go to Step 11

8

Measure resistance from the headlamp switch connector C2 cavity B (DK GRN) to ground.

Is the resistance less than the specified value?

5 ohms

Go to Step 13

Go to Step 9

9

Measure resistance from the headlamp switch connector C2 cavity C (BLK) to the instrument cluster connector C3 cavity D13 (BLK).

Is the resistance less than the specified value?

5 ohms

Go to Step 10

Go to Step 12

10

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

Is the headlamp switch replacement complete?

--

Go to Step 14

--

11

Repair the open in CKT 44 (DK GRN) between the instrument cluster and the headlamp switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 14

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12

Repair the open in CKT 470 (BLK) between the instrument cluster and the headlamp switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 14

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13

Repair the short to ground in CKT 44 (DK GRN) between the instrument cluster and the headlamp switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 14

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14

Operate the system in order to verify the repair. Did you correct the condition?

--

System OK.

Go to Step 2