GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the turn signal lever in the LEFT turn position.
  3. Place the turn signal lever in the RIGHT turn position.

Do the appropriate turn signal lamps and/or indicators illuminate for each action?

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

Go to Step 3

3

Is only one turn signal lamp inoperative?

Go to Step 6

Go to Step 4

4

Is only one of the turn signal indicators inoperative?

Go to Step 5

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Disconnect the instrument panel cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the inoperative turn signal supply voltage circuit of the IPC with a test lamp that is connected to a good ground.
  5. Place the turn signal lever in the position of the inoperative indicator.

Does the test lamp illuminate and flash.

Go to Step 10

Go to Step 13

6

  1. Disconnect the inoperative turn signal lamp.
  2. Probe the turn signal supply voltage circuit of the inoperative lamp with a test lamp that is connected to a good ground.
  3. Place the turn signal lever in the position of the inoperative lamp.

Does the test lamp illuminate and flash?

Go to Step 14

Go to Step 15

7

Do the hazard lamps operate properly?

Go to Step 8

Go to Hazard Lamps Inoperative

8

  1. Disconnect the turn/hazard-headlamp switch.
  2. Probe the turn signal flasher signal circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate and flash?

Go to Step 11

Go to Step 9

9

Test the turn signal flasher signal circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

10

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

Did you find and correct the condition?

Go to Step 19

Go to Step 16

11

Inspect for poor connections at the harness connector of the turn/hazard-headlamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 17

12

Inspect for poor connections at the harness connector of the turn/hazard-flasher. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

13

Repair an open, high resistance, or short to ground in the inoperative turn signal supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

--

14

Repair an open or high resistance in the ground circuit of the inoperative lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

--

15

Repair an open, high resistance, or short to ground in the inoperative turn signal supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

--

16

Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 19

--

17

Replace the turn/hazard-headlamp switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 19

--

18

Replace the turn/hazard-flasher.

Did you complete the replacement?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3