GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

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

Go to Step 2

Go to Symptoms - Lighting Systems

2

Verify that the headlamps are inoperative in low beams.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

With the headlamps in the ON position, test cavity 12 of the turn signal/headlamp switch for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 4

Go to Step 12

4

With the headlamps in the ON position, test C3 cavity 5 of the right instrument panel junction block for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 5

Go to Step 6

5

With the headlamps in the ON position, test C3 cavity 6 of the right instrument panel junction block for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 7

Go to Step 14

6

Repair the open in the low beam switch circuit between cavity 12 of the turn signal/headlamp switch and cavity 5 of C3. Refer to Circuit Testing .

Did you complete the repair?

Go to Step 16

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7

With the headlamps in the ON position, test cavity 5 of the daytime running lamp for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 8

Go to Step 9

8

With the headlamps in the ON position, test cavity A of the daytime running lamp for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 10

Go to Step 12

9

Repair the open in the low beam switch circuit between cavity 5 of the daytime running lamp control module and cavity 5 of C3. Refer to Circuit Testing .

Did you complete the repair?

Go to Step 16

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10

With the headlamps in the ON position, test cavity 1 of C200 for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 11

Go to Step 13

11

Repair the open in the low beam control circuit between cavity 1 of C200 and S120. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 16

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12

Replace the DRL control module. Refer to Daytime Running Lights (DRL) Control Module Replacement .

Did you complete the repair.

Go to Step 16

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13

Repair the open in the low beam control circuit between cavity A of the daytime running lamp control module and cavity 1 of C200. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 16

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14

Replace the instrument panel harness. Refer to Instrument Panel Wiring Harness Replacement .

Did you complete the replacement?

Go to Step 16

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15

Replace the turn signal/headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 16

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16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3