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 review the exterior lighting description and operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the turn signal switch in the LEFT TURN position.
  3. Place the turn signal switch in the RIGHT TURN position.

Do the turn signal lamps operate properly?

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

Go to Step 3

3

Is only one of the turn signal lamps/indicators inoperative?

Go to Step 4

Go to Step 5

4

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

Does the test lamp flash ON and OFF?

Go to Step 12

Go to Step 8

5

  1. Disconnect the turn signal/hazard flasher module.
  2. Probe the turn/hazard module supply voltage circuit of the turn signal/hazard flasher module with a test lamp that is connected to a good ground.
  3. Turn ON the turn signals.

Does the test lamp illuminate?

Go to Step 6

Go to Step 14

6

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

Does the test lamp illuminate?

Go to Step 7

Go to Step 15

7

  1. Connect a 15-amp fused jumper wire between the turn/hazard module supply voltage circuit of the turn/hazard flasher module and the turn/hazard module signal circuit of the turn/hazard flasher module.
  2. Place the turn signal switch in the LEFT TURN position.
  3. Place the turn signal switch in the RIGHT TURN position.

Do the left and right turn lamps illuminate with the proper switch position?

Go to Step 10

Go to Step 9

8

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

Did you find and correct the condition?

Go to Step 19

Go to Step 13

9

Test the turn/hazard module signal circuit of the inoperative turn signal bulb for a high resistance, an open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 11

10

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 16

11

Inspect for poor connections at the harness connector of 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 19

Go to Step 17

12

Inspect for poor connections at the inoperative turn signal bulb. 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 19

Go to Step 18

13

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 19

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14

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

Did you complete the repair?

Go to Step 19

--

15

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

Did you complete the repair?

Go to Step 19

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16

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

Did you complete the replacement?

Go to Step 19

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17

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 19

--

18

Replace the inoperative turn signal bulb.

Did you complete the replacement?

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 2