GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the headlamp leveling is inoperative.

Does the headlamp leveling operate normally?

--

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

Go to Step 3

3

Inspect the IGN E fuse in the underhood fuse block.

Is the fuse good?

--

Go to Step 5

Go to Step 4

4

Disconnect all components on all circuits fed off of the IGN E fuse and test the circuit for a short to ground. Refer to Power Distribution Schematics and Circuit Testing in Wiring Systems.

Was a problem found?

--

Go to Step 5

Go to Step 7

5

Locate and repair the circuit shorted to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

--

6

Test each component and replace the shorted component fed off of the IGN E fuse circuit causing the short to ground. Refer to Circuit Testing in Wiring Systems.

Is the repair complete?

--

Go to Step 20

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7

With ignition switch in RUN, connect a test lamp from ground to terminal 3 of the headlamp leveling actuator connector (RH/LH). Refer to Circuit Testing in Wiring Systems.

Does the lamp light?

--

Go to Step 9

Go to Step 8

8

Locate and repair open circuit in CKT 639 (PNK) from headlamp leveling actuator to underhood fuse block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

--

9

Connect a J 39200 Digital Multimeter (DMM) from ground to terminal 1 of the headlamp actuator connector (RH/LH) and check for continuity. Refer to Circuit Testing in Wiring Systems.

Is there continuity?

--

Go to Step 11

Go to Step 10

10

Locate and repair open circuit in CKT 350 (BLK) from headlamp actuator to G102 ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

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11

Connect a DMM from ground to terminal 2 of the headlamp leveling actuator connector (RH/LH) and adjust the headlamp leveling switch from highest to lowest setting. Refer to Circuit Testing in Wiring Systems.

Does the DMM indicate within the specified range?

2.0 V-8.0 V

Go to Step 12

Go to Step 13

12

Replace headlamp leveling actuator (RH/LH) as applicable. Refer to Headlamp Motor/Actuator Replacement .

Is the repair complete?

--

Go to Step 20

--

13

Connect a J 39200 DMM from ground to terminal 31A of the headlamp leveling switch and check for continuity. Refer to Circuit Testing in Wiring Systems.

Is there continuity?

--

Go to Step 15

Go to Step 14

14

Locate and repair open in CKT 1850 from switch to G203 ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

--

15

Connect a test lamp from ground to terminal 56B of the headlamp leveling switch connector. Refer to Circuit Testing in Wiring Systems.

Does the lamp light?

--

Go to Step 17

Go to Step 16

16

Locate and repair the open in CKT 639 (PNK) between the switch and the underhood fuse block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

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17

Connect a test lamp from ground to terminal G of the headlamp leveling switch connector. Refer to Circuit Testing in Wiring Systems.

Does the lamp light?

--

Go to Step 19

Go to Step 18

18

Replace headlamp leveling switch. Refer to Headlamp Leveling Switch Replacement .

Is the repair complete?

--

Go to Step 20

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19

Locate and repair the open in CKT 189 (DK GRN) between the switch and the headlamp leveling actuator (RH/LH). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 20

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20

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3