GM Service Manual Online
For 1990-2009 cars only

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Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition switch to the ON position.
  2. Place the turn signal switch in the LH and RH on position.

Do the turn signals operate properly?

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

Go to Step 3

3

Are all of the turn signal lamps and indicators inoperative?

Go to Step 5

Go to Step 4

4

Are only the turn signal indicators inoperative?

Go to Step 20

Go to Step 9

5

Check the TURN SIGNALS CORN LPS fuse for an open.

Is the TURN SIGNALS CORN LPS fuse open?

Go to Step 27

Go to Step 6

6

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

Does the test lamp illuminate?

Go to Step 7

Go to Step 18

7

Connect a test lamp between the turn/hazard module supply voltage circuit of the hazard lamp/turn signal lamp flasher and the ground circuit of the hazard lamp/turn signal lamp flasher .

Does the test lamp illuminate?

Go to Step 8

Go to Step 25

8

  1. Install a fused jumper between the turn/hazard module supply voltage circuit of the hazard lamp/turn signal lamp flasher and the turn signal flasher signal circuit of the hazard lamp/turn signal lamp flasher.
  2. Place the turn signal switch in the RH on position and the LH on position.

Do the turn signal lamps illuminate?

Go to Step 21

Go to Step 17

9

Are the front turn signals inoperative?

Go to Step 10

Go to Step 14

10

  1. Turn the ignition to the OFF position.
  2. Apply the parking brake.
  3. Turn the ignition switch to the ON position.
  4. Disconnect the inoperative front turn signal lamp.
  5. Connect a test lamp between the supply voltage circuit of the inoperative front turn signal lamp and a good ground.
  6. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?

Go to Step 15

Go to Step 11

11

  1. Disconnect the Body Control Module (BCM) connector.
  2. Connect a test lamp between the turn signal supply voltage circuit of the BCM and ground.
  3. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?

Go to Step 13

Go to Step 12

12

Test for an open or high resistance in the turn signal switch signal of the BCM . Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 22

13

Test for an open or high resistance in the turn signal lamp supply voltage circuit of the inoperative front turn signal lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 37

14

  1. Turn the ignition switch to the ON position.
  2. Disconnect the inoperative rear turn signal lamp.
  3. Connect a test lamp between the supply voltage circuit of the inoperative turn signal lamp and a good ground.
  4. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?

Go to Step 15

Go to Step 16

15

Connect a test lamp between the ground circuit of the inoperative turn signal lamp and the turn signal lamp supply voltage circuit of the inoperative turn signal lamp.

Does the test lamp illuminate?

Go to Step 24

Go to Step 30

16

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

Did you find and correct the condition?

Go to Step 38

Go to Step 22

17

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

Did you find and correct the condition?

Go to Step 38

Go to Step 22

18

With a test lamp connected to ground, backprobe the ignition 1 voltage circuit of connector C201 that supplies the turn signal switch.

Does the test lamp illuminate?

Go to Step 19

Go to Step 31

19

With a test lamp connected to ground, backprobe the turn/hazard module supply voltage circuit of connector C201.

Does the test lamp illuminate?

Go to Step 32

Go to Step 22

20

  1. Turn OFF the ignition.
  2. Disconnect the Instrument Panel Cluster (IPC).
  3. Connect a test lamp between the turn signal supply voltage circuit of the inoperative turn signal indicator and the Instrument Panel Cluster (IPC) ground circuit.
  4. Turn ON the ignition.
  5. Place the turn signal switch in the appropriate ON position.

Does the test lamp flash ON and OFF?

Go to Step 23

Go to Step 26

21

Inspect for poor connections at the harness connector of the hazard lamp/turn signal lamp 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 38

Go to Step 34

22

Inspect for poor connections at the 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 38

Go to Step 33

23

Inspect for poor connections at the Instrument Panel Cluster (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 38

Go to Step 35

24

Inspect for poor connections at the inoperative turn signal lamp. 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 38

Go to Step 36

25

Repair the open or high resistance in the ground circuit of the hazard lamp/turn signal lamp flasher. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

26

Repair an open or high resistance in the turn signal lamp supply voltage circuit of the inoperative turn signal indicator. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

27

Test for a short to ground in the ignition 1 voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 28

28

Test for a short to ground in the turn/hazard flasher supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

Go to Step 29

29

Repair a short to ground in the turn signal lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

30

Repair the open or high resistance in the ground circuit of the inoperative signal turn lamp. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 38

--

31

Repair the open or high resistance in the ignition 1 voltage circuit of the turn signal switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

--

32

Repair the open or high resistance in the turn/hazard module supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 38

--

33

Replace the turn signal switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 38

--

34

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

Did you complete the replacement?

Go to Step 38

--

35

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

Did you complete the repair?

Go to Step 38

--

36

Replace the inoperative turn signal lamp. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement or Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement .

Did you complete the replacement?

Go to Step 38

--

37

Important: Preform the set up procedures for the Body Control Module (BCM) . Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 38

--

38

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2