GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: : This table diagnoses inoperative turn signals on one side. It assumes that the cornering lamps, hazard lamps, and turn signals on the other side all operate properly.

1

Did you perform the Lighting System Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Move the turn signal level to the inoperative position.
  3. Observe the appropriate cornering lamp.

Did the appropriate cornering lamp illuminate?

--

Go to Step 3

Go to Step 7

3

  1. Turn OFF the ignition.
  2. Connect a test lamp between the appropriate turn signal input circuit at the turn signal/hazard flasher module connector and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Move the turn signal level to the inoperative position.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 10

4

  1. Turn OFF the ignition.
  2. Connect a test lamp between the appropriate turn signal output circuit at the turn signal/hazard flasher module connector and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Move the turn signal level to the inoperative position.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 5

5

Inspect for poor connections at 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 12

Go to Step 6

6

Replace the turn signal/hazard flasher module. Refer to Hazard Lamp Flasher Replacement .

Did you complete the replacement?

--

Go to Step 12

--

7

  1. Turn OFF the ignition.
  2. Connect a test lamp between the appropriate turn signal input circuit at the turn signal switch connector and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Move the turn signal level to the inoperative position.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 8

8

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 12

Go to Step 9

9

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

Did you complete the replacement?

--

Go to Step 12

--

10

Repair the open in the appropriate turn signal input circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

11

Repair the open in the appropriate turn signal output circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you find and correct the condition?

--

System OK

Go to Step 2