GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Exterior Lighting Systems Description and Operation and perform the necessary inspections?

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Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

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

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

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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?

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Go to Step 4

Go to Step 6

4

Test the inoperative front turn signal switch signal circuit to the IPC for an open or high resistance. Refer to Circuit Testing in Wiring Systems.

Did you find a problem?

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Go to Step 14

Go to Step 5

5

  1. Inspect the inoperative bulb/socket in the IPC for poor terminal contact or an open filament and replace as necessary. Refer to Instrument Cluster Bulb Replacement .
  2. If a problem is not found, replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the repair?

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Go to Step 23

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6

Is only one turn signal lamp inoperative?

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Go to Step 7

Go to Step 8

7

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

Did you find a problem?

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Go to Step 19

Go to Step 15

8

Inspect the TURN fuse in the IP fuse block.

Is the fuse open?

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Go to Step 13

Go to Step 9

9

  1. Turn the ignition and the start switch to the RUN position
  2. Test the ignition 1 voltage circuit to the multifunction switch turn signal switch for an open or high resistance. Refer to Circuit Testing in Wiring Systems.

Did you find a problem?

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Go to Step  16

Go to Step 10

10

  1. Activate the multifunction switch turn signal switch.
  2. Test the turn/hazard module supply voltage circuit for voltage at the multifunction switch, the turn signal switch. Refer to Circuit Testing in Wiring Systems.

Is the specified voltage present?

B+

Go to Step 11

Go to Step 20

11

Test for an open or high resistance in the following circuits, and refer to Circuit Testing in Wiring Systems:

    • The turn/hazard module supply voltage
    • The turn signal lamp flasher ground

Did you find a problem?

--

Go to Step 17

Go to Step 12

12

  1. Disconnect the multifunction/turn signal switch.
  2. Place the multifunction switch turn signal switch in the LH turn position.
  3. Test the multifunction switch turn signal switch for continuity between the multifunction switch turn signal switch flasher module input terminal and the left front turn signal switch output terminal. Refer to Circuit Testing in Wiring Systems.

Is continuity present?

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Go to Step 21

Go to Step 20

13

Test the following circuits for a short to ground. Refer to Circuit Testing in Wiring Systems:

    • The multifunction turn signal switch ignition 1 voltage
    • The turn/hazard module supply voltage
    • The turn/hazard module 2 supply voltage
    • The turn/hazard module signal
    • The left front turn signal switch signal
    • The right front turn signal switch signal
    • The left rear turn signal switch signal
    • The right rear turn signal switch signal

Did you find a problem?

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Go to Step 18

Go to Step 21

14

Repair the open or high resistance in the inoperative front turn signal switch signal circuit to the IPC. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step  22

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15

Repair the following conditions, and refer to Wiring Repairs in Wiring Systems:

    • An open in the supply voltage circuit, or in the ground circuit of the turn signal lamp
    • A high resistance in the supply voltage circuit, or in the ground circuit of the turn signal lamp
    • A short to ground in the turn signal lamp supply voltage circuit

Did you complete the repair?

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Go to Step 22

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16

Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

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17

Repair the open or high resistance in one of the following circuits, and refer to Wiring Repairs in Wiring Systems:

    • Both of the turn/hazard modules supply voltage
    • The turn signal lamp flasher ground

Did you complete the repair?

--

Go to Step 22

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18

Repair the short to ground found in one of the following circuits, and refer to Wiring Repairs in Wiring Systems:

    • The multifunction turn signal switch ignition 1 voltage
    • The turn/hazard module supply voltage
    • The turn/hazard module 2 supply voltage
    • The turn/hazard module signal
    • The left front turn signal switch signal
    • The right front turn signal switch signal
    • The left rear turn signal switch signal
    • The right rear turn signal switch signal

Did you complete the repair?

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Go to Step 22

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19

Replace or repair the inoperative bulb/socket.

Did you complete the repair?

--

Go to Step 22

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20

Replace the multifunction turn signal switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column.

Did you complete the repair?

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Go to Step 22

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21

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

Did you complete the repair?

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Go to Step 22

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22

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3