GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the fault is present.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Turn the hazard lights on.

Do the hazard lights function properly?

Go to Step 11

Go to Step 4

4

Remove the TURN fuse and inspect. Refer to Testing for Short to Ground in Wiring Systems.

Is the fuse open?

Go to Step 20

Go to Step 5

5

  1. Re-install the fuse.
  2. Connect a test lamp between the fused ignition positive voltage circuit at C201A to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 19

6

  1. Turn the left turn signal on.
  2. Connect a test lamp between the turn signal/flasher feed circuit at C201A to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 22

7

  1. Gain access to the back of the fuse block.
  2. Connect a test lamp from (back probe) between the turn signal/flasher feed circuit and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 18

8

Connect a test lamp between the flasher ground circuit and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 9

Go to Step 17

9

Connect a test lamp (back probe) between the turn/hazard flasher output circuit and a good ground at the fuse block.

Does the test lamp illuminate or flash?

Go to Step 10

Go to Step 21

10

Connect a test lamp between the turn/hazard flasher output circuit at C201A and to a good ground.

Does the test lamp illuminate or flash?

Go to Step 22

Go to Step 16

11

Remove the TURN fuse and inspect. Refer to Testing for Short to Ground in Wiring Systems.

Is the fuse open?

Go to Step 14

Go to Step 12

12

  1. Reinstall the fuse.
  2. Connect a test lamp from (back probe) between the fused ignition positive voltage circuit at C201A and to a ground.

Does the test lamp illuminate?

Go to Step 13

Go to Step 15

13

  1. Turn the left turn signal on.
  2. Connect a test lamp from (back probe) between the turn signal/flasher feed circuit at C201 and to a good ground.

Does the test lamp illuminate?

Go to Step 16

Go to Step 22

14

  1. Repair the short to ground in the fused ignition positive voltage circuit or the turn signal/flasher feed circuit. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse.

Did you complete the repair?

Go to Step 23

--

15

Repair the open in the fused ignition positive voltage circuit between the turn/hazard switch and the fuse. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

16

Repair the open in the turn/hazard flasher output circuit between the fuse block and the switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

17

Repair the open in the flasher ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

18

Repair the open in the turn signal/flasher circuit between the fuse block and the switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

19

Repair the open in the fused ignition positive voltage circuit between the turn/hazard switch and the fuse. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

20

  1. Repair the short to ground in the fused ignition positive voltage circuit of in the turn signal/flasher feed circuit. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse.

Did you complete the repair?

Go to Step 23

--

21

Replace the turn/hazard flasher.

Did you complete the repair?

Go to Step 23

--

22

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

Did you complete the replacement?

Go to Step 23

--

23

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3