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 ON the ignition, with the engine OFF.
  2. Observe the turn signal lamps and indicators.
  3. Turn ON and OFF the right and left turn signal lamps.

Do the turn signal lamps and indicators operate properly?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Are all of the turn signals and indicators inoperative?

Go to Step 5

Go to Step 4

4

Are only the turn signal indicators inoperative?

Go to Step 12

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Disconnect the turn signal/hazard flasher module.
  3. Connect a test lamp between the turn signal/hazard flasher module supply voltage circuit and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 6

Go to Step 20

6

  1. Turn OFF the ignition.
  2. Connect a test lamp between the supply voltage circuit of the turn signal/hazard flasher module and the ground circuit of the turn signal/hazard flasher module.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 10

Go to Step 21

7

  1. Turn OFF the ignition.
  2. Disconnect the inoperative turn signal bulb.
  3. Connect a test lamp between the supply voltage circuit of the inoperative turn signal bulb and the ground circuit of the inoperative turn signal bulb.
  4. Turn ON the inoperative turn signal.

Does the test lamp flash ON and OFF?

Go to Step 19

Go to Step 8

8

Test the inoperative turn signal supply voltage circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 27

Go to Step 9

9

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

Did you find and correct the condition?

Go to Step 27

Go to Step 10

10

  1. Turn OFF the ignition.
  2. Disconnect the multifunction, turn signal switch.
  3. Connect a test lamp between the ignition 1 voltage circuit of the multifunction, turn signal switch and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 11

Go to Step 22

11

  1. Turn OFF the ignition.
  2. Reconnect the multifunction, turn signal switch.
  3. Disconnect the turn signal/hazard flasher module.
  4. Connect a test lamp between the inoperative turn signal switch signal circuit of the turn signal/hazard flasher module and a good ground.
  5. Turn ON the inoperative turn signal.

Does the test lamp illuminate?

Go to Step 16

Go to Step 13

12

  1. Turn OFF the ignition.
  2. Disconnect the instrument panel cluster (IPC).
  3. Connect a test lamp between the turn signal lamp supply voltage circuit of the inoperative turn indicator and the IPC ground circuit.
  4. Turn ON the inoperative turn signal indicator.

Does the test lamp flash ON and OFF?

Go to Step 18

Go to Step 14

13

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

Did you find and correct the condition?

Go to Step 27

Go to Step 17

14

Test the turn signal lamps supply voltage circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 27

Go to Step 15

15

Test the IPC ground circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 27

Go to Step 16

16

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

Did you find and correct the condition?

Go to Step 27

Go to Step 23

17

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

Did you find and correct the condition?

Go to Step 27

Go to Step 24

18

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

Did you find and correct the condition?

Go to Step 27

Go to Step 25

19

Inspect for poor connections at the inoperative turn signal bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 27

Go to Step 26

20

Repair the open, high resistance or short to ground in the turn signal/hazard flasher module supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 27

--

21

Repair the open or high resistance in the turn signal/hazard flasher module ground circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 27

--

22

Repair the open in the ignition 1 voltage circuit of the multifunction, turn signal switch. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 27

--

23

Replace the turn signal/hazard flasher module. Refer to Hazard and Turn Signal Flasher Replacement .

Did you complete the replacement?

Go to Step 27

--

24

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

Did you complete the replacement?

Go to Step 27

--

25

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

Did you complete the replacement?

Go to Step 27

--

26

Replace the inoperative turn signal bulb. Refer to Park/Turn Signal Lamp Bulb Replacement and Tail Lamp Replacement .

Did you complete the replacement?

Go to Step 27

--

27

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2