GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Schematic Reference: Headlight Leveling Schematics

Connector End View Reference: Lighting Systems Connector End Views

1

Did you review the Exterior Lighting Systems Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

Verify that the headlight leveling is inoperative.

Does the headlight leveling operate normally?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Inspect the IGN E fuse.

Is the fuse good?

--

Go to Step 4

Go to Step 10

4

With ignition switch in RUN, test the ignition 1 voltage circuit at the headlamp inoperative leveling actuator connector. Refer to Circuit Testing .

Is the specified voltage present?

B+

Go to Step 5

Go to Step 11

5

Test the ground circuit at the inoperative headlamp actuator connector for continuity to ground. Refer to Circuit Testing .

Is continuity present?

--

Go to Step 6

Go to Step 12

6

Connect a digital multimeter (DMM) from ground to the headlamp leveling motor supply voltage circuit at the inoperative headlamp leveling actuator connector and adjust the headlamp leveling switch from the highest to lowest setting. Refer to Circuit Testing .

Does the DMM display within the specified range?

2.0 V-8.0 V

Go to Step 16

Go to Step 7

7

Test the ground circuit of the headlamp leveling switch for continuity to ground. Refer to Circuit Testing .

Is there continuity?

--

Go to Step 8

Go to Step 13

8

Test the ignition 1 voltage circuit at the headlamp leveling switch connector. Refer to Circuit Testing .

Is the specified voltage present?

B+

Go to Step 9

Go to Step 15

9

With the ignition switch in the OFF position, test for an open, high resistance, short to ground, or short to voltage in the headlamp leveling motor supply voltage circuit. Refer to Circuit Testing .

Did you find a condition?

--

Go to Step 14

Go to Step 17

10

Repair the short to ground in the ignition 1 voltage circuit. Refer to Wiring Repairs and Power Distribution Schematics .

Did you complete the repair?

--

Go to Step 18

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11

Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs .

Is repair complete?

--

Go to Step 18

--

12

Repair the open or high resistance in the ground circuit. Refer to Wiring Repairs .

Is repair complete?

--

Go to Step 18

--

13

Repair the open or high resistance in the ground circuit. Refer to Wiring Repairs .

Is repair complete?

--

Go to Step 18

--

14

Repair open, high resistance, short to ground, or short to voltage in the headlamp leveling motor supply voltage circuit. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 18

--

15

Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 18

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16

Replace the inoperative headlamp leveling actuator. Refer to Headlamp Replacement .

Is repair complete?

--

Go to Step 18

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17

Replace headlamp leveling switch. Refer to Headlamp Switch Replacement .

Did you complete the repair?

--

Go to Step 18

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18

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3