GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Interior Lights Dimming Circuit Description and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

Verify that the Instrument Panel lamps are inoperative.

Do the Instrument Panel lamps operate normally?

Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the Lamp Dimmer Control connector.
  2. Turn the Headlamp Switch to the PARK position.
  3. Use a J 39200 to measure the voltage between cavity 2 of the Lamp Dimmer Control and ground.

Is battery positive voltage present?

Go to Step 4

Go to Step 5

4

  1. Turn the Dimmer Control Switch to full intensity.
  2. Use a J 39200 to measure the voltage between cavity 4 of the Lamp Dimmer Control and ground.

Is battery positive voltage present?

Go to Step 6

Go to Step 7

5

Use a J 39200 to measure the voltage between C216, cavity 22 of the Light Switch and ground.

Is battery positive voltage present?

Go to Step 8

Go to Step 9

6

Test for an open condition between cavity 3 and S254 of the IP Lamp Dimmer Control.

Does an open condition exist?

Go to Step 11

Go to Step 12

7

  1. Disconnect the IP Lamp Dimmer Control connector.
  2. Test for continuity between cavity 2 of the Dimmer Switch and Cavity 4.

Does continuity exist?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 10

8

With the Light Switch in the PARK position.

Test for a short to ground condition between C216 cavity 17 and ground.

Does a short to ground condition exist?

Go to Step 13

Go to Testing for Intermittent Conditions and Poor Connections

9

Repair the open between the Junction Block C5 cavity 3 and S213. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

10

Replace the IP Lamp Dimmer Control.

Did you complete the repair?

Go to Step 16

--

11

Repair the open between the Lamp Dimmer Control and splice S254. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

12

Connect a fused jumper between C216, cavity 17 and C216, cavity 22 of the Light Switch.

Do the Instrument Panel lamps illuminate?

Go to Step 14

Go to Step 15

13

Repair the open in the BLK wire between C216, cavity 17 and S207. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

14

Replace the Light Switch.

Did you complete the repair?

Go to Step 16

--

15

Repair the open between C216, cavity 22 and S239. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3