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 park lamps are inoperative.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Test cavity 10 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 15

4

With the parklamp switch in the ON position, test cavity 13 of the turn signal/headlamp switch for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 5

Go to Step 16

5

With the parklamp switch in the ON position, test cavity 13 of the daytime running lamp control module for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 6

Go to Step 14

6

With the parklamp switch in the ON position, test cavity 12 of the daytime running lamp control module for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 7

Go to Step 17

7

With the parklamp switch in the ON position, test cavity 2 of the TAIL relay for continuity to ground. Refer to Circuit Testing .

Is a ground present?

Go to Step 8

Go to Step 13

8

Test C8 cavity 7 of the instrument panel fuse block for battery positive voltage. Refer to Circuit Testing .

Is voltage present?

Go to Step 9

Go to Step 18

9

Test cavity 1 and 3 of the TAIL relay for battery positive voltage. Refer to Circuit Testing .

Is voltage present?

Go to Step 10

Go to Step 12

10

Test cavity 5 of the TAIL relay for battery positive voltage. Refer to Circuit Testing .

Is voltage present?

Go to Step 11

Go to Step 19

11

Repair the open in the TAIL relay output voltage circuit. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 20

--

12

Repair the open in the TAIL relay supply voltage circuit. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 20

--

13

Repair the open in the tail relay control circuit between cavity 12 of the daytime running lamps control module and cavity 2 of the TAIL relay. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 20

--

14

Repair the open in the park lamp signal circuit between cavity 13 of the daytime running lamps control module and cavity 13 of the turn signal/headlamp switch. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 20

--

15

Repair the open in the turn signal/headlamp switch ground circuit. Refer to Circuit Testing .

Did you complete the repair?

Go to Step 20

--

16

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

Did you complete the repair?

Go to Step 20

--

17

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

Did you complete the repair?

Go to Step 20

--

18

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

Did you complete the repair?

Go to Step 20

--

19

Replace the TAIL relay.

Did you complete the repair?

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3