GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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).
  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 14

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 15

Go to Step 16

7

Do the hazard lamps operate properly?

Go to Step 8

Go to Hazard Lamps Inoperative

8

  1. Disconnect the headlamp/turn signal 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 12

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 20

Go to Step 13

10

Inspect the bulb of the inoperative turn signal indicator. Replace if necessary.

Did you find and correct the condition?

Go to Step 20

Go to Step 11

11

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 20

Go to Step 17

12

Inspect for poor connections at the harness connector of the headlamp/turn signal 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 20

Go to Step 18

13

Inspect for poor connections at the harness connector of the hazard 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 20

Go to Step 19

14

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 20

--

15

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 20

--

16

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 20

--

17

Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

Go to Step 20

--

18

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

Did you complete the replacement?

Go to Step 20

--

19

Replace the hazard switch. Refer to Hazard Lamp Flasher Replacement .

Did you complete the replacement?

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