GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

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

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Go to Step 5

Go to Step 2

2

  1. Turn the ignition switch to the RUN.
  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.

Is the test light flashing?

--

Go to Step 4

Go to Step 3

3

    • If the left side is inoperative, repair a poor connection or an open in circuit 18.
    • If the right side is inoperative, repair a poor connection or an open in circuit 19.

Has the repair been made?

--

Go to Exterior Lights System Check

--

4

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

Has the repair been made?

--

Go to Exterior Lights System Check

--

5

Inspect the turn telltale light flash.

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

--

Go to Step 7

Go to Step 6

6

    • If the left side is inoperative, repair a poor connection or an open in circuit 14 between C201 terminal A7 and S290.
    • If the right side is inoperative, repair a poor connection or open in circuit 15 between C201 terminal A6 and S289.

Has the repair been made?

--

Go to Exterior Lights System Check

--

7

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal switch to the inoperative side:
  3. • If the left side is inoperative: using a test light, backprobe between the underhood electrical center harness connector C2 terminal F9 to ground.
    • If the right side is inoperative: using a test light, backprobe between the underhood electrical center harness connector C2 terminal F10 to ground

Does the test light flash?

--

Go to Step 9

Go to Step 12

8

    • If the left side is inoperative, repair a poor connection an open in circuit 14 between S290 and the underhood electrical center connector C2 terminal F9.
    • If the right side is inoperative, repair a poor connection or an open in circuit 15 between S289 and the underhood electrical center connector C2 terminal F10.

Has the repair been made?

--

Go to Exterior Lights System Check

--

9

  1. Turn the ignition switch to the RUN position.
  2. Place the turn signal switch to the inoperative side:
  3. • If the left side is inoperative: using a test light, backprobe between the underhood electrical center harness connector C3 terminal B9 to ground.
    • If the right side is inoperative: using a test light, backprobe between the underhood electrical center harness connector C3 terminal B10 and ground.

Does the test light flash?

--

Go to Step 11

Go to Step 10

10

Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Has the repair been made?

--

Go to Exterior Lights System Check

--

11

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

Does the test light flash?

--

Go to Step 12

Go to Step 13

12

Replace the park/turn lamp. Refer to Park/Turn Signal Lamp Bulb Replacement .

Has the repair been made?

--

Go to Exterior Lights System Check

--

13

    • If the left side is inoperative, repair a poor connection or an open in circuit 14 between the underhood electrical center connector terminal B9 and the park turn lamp connector terminal A.
    • If the right side is inoperative, repair a poor connection or an open in circuit 15 between the underhood electrical center connector C3 terminal B10 and the park/turn lamp connector terminal A.

Has the repair been made?

--

Go to Exterior Lights System Check

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