GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn on the ignition.
  2. Place the turn signal switch to the left-turn position, and then to the right-turn position.

Do the turn lamps turn on in both positions?

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Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Is the turn signal lamp that is inoperative a front turn signal lamp?

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Go to Step 7

Go to Step 4

4

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal switch to the inoperative side.
  3. Using a test light, backprobe between the inoperative tail lamp harness connector terminal A and ground.

Does the test light flash?

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Go to Step 6

Go to Step 5

5

Repair a poor connection or an open in the turn signal switch feed circuit, between the inoperable turn lamp and the turn signal switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 20

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6

Replace the tail/stop/turn lamp. Refer to Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement .

Did you complete the repair?

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Go to Step 20

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7

Inspect the turn telltale light.

Does the turn telltale light flash for the inoperative side when the turn signal is ON?

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Go to Step 9

Go to Step 8

8

Repair a poor connection or an open in the turn signal switch feed circuit, between the turn signal switch and the splice. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 20

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9

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal switch to the inoperative side.
  3. Using a test lamp connection to a known good ground, backprobe the inoperable turn signal switch feed circuit at the body control module harness connector.

Does the test lamp flash?

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Go to Step 11

Go to Step 10

10

Repair a poor connection or an open in the turn signal switch feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 20

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11

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal switch to the inoperative side.
  3. Using a test lamp connection to a known good ground, backprobe the turn signal circuit at the body control module harness connector.

Does the test lamp flash?

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Go to Step 13

Go to Step 12

12

Important: Perform the setup procedure for the body control module.

Replace the body control module. Refer to Body Control Module Replacement .

Did you complete the repair?

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Go to Step 20

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13

  1. Turn the ignition to the RUN position.
  2. Place the turn signal to the inoperative side.
  3. Using a test lamp connection to a known good ground, backprobe the turn signal circuit at the underhood accessory wiring junction block harness connector C2.

Does the test lamp flash?

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Go to Step 15

Go to Step 14

14

Repair a poor connection or an open in the turn signal circuit between the body control module connector and the underhood accessory wiring junction block connector C2.

Did you complete the repair?

--

Go to Step 20

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15

  1. Turn the ignition to the RUN position.
  2. Place the turn signal to the inoperative side.
  3. Using a test lamp connection to a known good ground, backprobe the turn signal switch at the underhood accessory wiring junction block harness connector C3.

Does the test light flash?

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Go to Step 17

Go to Step 16

16

Replace the underhood accessory wiring junction block.

Did you complete the repair?

--

Go to Step 20

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17

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal to the inoperative side.
  3. Using a test light connected to a known good ground, backprobe the turn signal switch circuit at the inoperative side headlamp harness connector.

Does the test light flash?

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Go to Step 18

Go to Step 19

18

Replace the headlamp. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement .

Did you complete the repair?

--

Go to Step 20

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19

Repair a poor connection or an open in the turn signal switch circuit between the underhood accessory wiring junction block connector C3 and the inoperable turn lamp.

Did you complete the repair?

--

Go to Step 20

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20

Operate the system in order to verify the repair.

Did you correct the condition?

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Go to Diagnostic System Check - Lighting Systems

Go to Step 2