GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn the ignition to the RUN position.
  2. Turn the turn signal switch to the TURN LEFT position and then to the TURN RIGHT position.

Do the turn signal lamps and the turn signal indicators flash?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are only the turn signal indicators inoperative?

Go to Step 5

Go to Step 4

4

Is only one turn lamp inoperative?

Go to Step 11

Go to Step 6

5

  1. Leave the turn signal switch at the inoperative side.
  2. Using a test lamp, backprobe the supply voltage circuit of the turn signal lamp indicator at the instrument panel cluster (IPC).

Does the test lamp flash?

Go to Step 10

Go to Step 12

6

  1. Disconnect connector C201.
  2. Using a test lamp connected to a ground, probe the turn signal battery positive voltage supply circuit.
  3. Turn the ignition switch to the RUN position.

Does the test lamp illuminate?

Go to Step 7

Go to Step 14

7

  1. Using a test lamp, probe between the turn signal battery positive voltage supply circuit and the left turn signal switch.
  2. Turn the ignition to the RUN position.

Does the test lamp flash ON and OFF?

Go to Step 8

Go to Step 9

8

Inspect for poor connection at the hazard flasher. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct and the condition?

Go to Step 18

Go to Step 16

9

Inspect for poor connection at the harness connector of the turn signal switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct and the condition?

Go to Step 18

Go to Step 17

10

Inspect for poor connection at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct and the condition?

Go to Step 18

Go to Step 15

11

Test the inoperative turn signal switch signal circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 18

Go to Step 13

12

Repair the short to ground or open in the inoperative turn signal lamp indicator power supply circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 18

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13

Repair the open or short to ground in the inoperative turn signal lamp power supply or ground circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 18

--

14

Repair the open or short to ground in the battery positive voltage turn signal supply circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 18

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15

Replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 18

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16

Replace the hazard flasher.

Did you complete the replacement?

Go to Step 18

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17

Replace the turn signal switch. Refer to Turn Signal Multifunction Switch Replacement .

Did you complete the replacement?

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