GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that one of the stoplamps is inoperative.

Do the stoplamps operate normally?

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

Go to Step 3

3

  1. Disconnect the inoperative bulb.
  2. Inspect the bulb.

Is the bulb open?

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Go to Step 7

Go to Step 4

4

Connect a J 39200 Digital Multimeter (DMM) between terminal G of the inoperative lamp socket and ground and check for continuity. Refer to Circuit Testing in Wiring Systems.

Is there continuity?

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Go to Step 6

Go to Step 5

5

Locate and repair the open or high resistance in CKT 1750 (BLK) or CKT 2250 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 13

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6

  1. Connect a test lamp between ground and cavity A of the inoperative lamp socket. Refer to Circuit Testing in Wiring Systems.
  2. Apply the service brakes.

Does the test lamp illuminate?

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Go to Step 7

Go to Step 8

7

Replace the bulb.

Is the repair complete?

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Go to Step 13

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8

Test for open, high resistance or short to ground in CKT 618 (YEL) (LH side) or CKT 619 (DK GRN) (RH side). Refer to Circuit Testing in Wiring Systems.

Was a problem found?

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Go to Step 9

Go to Step 10

9

Repair the open, high resistance or short to ground in CKT 618 (YEL) (LH side) or CKT 619 (DK GRN) (RH side). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 13

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10

Test for open or high resistance in CKT 1418 (YEL/BLK) (LH side) or CKT 1419 (DK GRN/WHT) (RH side). Refer to Circuit Testing in Wiring Systems.

Was a problem found?

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Go to Step 11

Go to Step 12

11

Repair the open or high resistance in CKT 1418 (YEL/BLK) (LH side) or CKT 1419 (DK GRN/WHT) (RH side). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 13

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12

Replace the Multifunction Switch (Turn Signal Switch). Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Standard or Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Is the repair Complete?

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Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3