GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console or Power Door Systems Connector End Views in Doors

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the turn signal lamps and/or indicators are inoperative.

Do the turn signal lamps and/or indicators operate normally?

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

Go to Step 3

3

Are only the turn signal indicators in the instrument panel cluster (IPC) inoperative?

Go to Step 4

Go to Step 5

4

Test the inoperative turn signal supply voltage circuit to the I/P cluster for an open or high resistance. 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

5

Is only 1 turn signal lamp inoperative?

Go to Step 6

Go to Step 8

6

Inspect the inoperative bulb/socket for an internal short, poor terminal contact, or an open filament.

Was a problem found?

Go to Step 16

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 19

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8

Inspect the FLASH and IGN E fuses.

Is either fuse open?

Go to Step 11

Go to Step 9

9

Test for an open or high resistance in the following circuits:

    • The turn signal hazard flasher module battery positive supply voltage
    • The turn signal hazard flasher module ground
    • The turn signal switch ignition 1 supply voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 10

10

  1. Disconnect the multifunction switch turn signal switch.
  2. Test the multifunction turn signal switch for continuity between the multifunction turn signal switch ignition 1 voltage input terminal and the turn signal flasher signal output terminal in each respective position. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

Go to Step 11

Go to Step 13

11

Test the following circuits for an open, high resistance or short to ground:

    • The multifunction turn signal switch ignition 1 voltage
    • The turn signal hazard flasher module supply voltage
    • The left turn flasher signal
    • The right turn flasher signal
    • The left turn lamp supply voltage
    • The right turn lamp supply voltage
    • The left rear turn/stop lamp supply voltage
    • The right rear turn/stop lamp supply voltage
    • The left trailer stop/turn lamp supply voltage
    • The right trailer stop/turn lamp supply voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 14

12

Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 15

13

Inspect for poor connections at the multifunction turn signal switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 17

14

Inspect for poor connections at the turn signal hazard flasher module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 18

15

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

Did you complete the repair?

Go to Step 19

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16

Replace or repair the inoperative bulb/socket.

Did you complete the repair?

Go to Step 19

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17

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

Did you complete the repair?

Go to Step 19

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18

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

Did you complete the repair?

Go to Step 19

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19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3