GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Exterior Lights System Check?

--

Go to Step 2

Go to Exterior Lights System Check

2

Inspect the STOP LP fuse at the underhood fuse block.

Is the STOP LP fuse good?

--

Go to Step 4

Go to Step 3

3

Locate and repair short to ground in CKT 1540 (ORN) and/or CKT 17 (WHT).

Is the repair complete?

--

Go to Exterior Lights System Check

--

4

Connect a test lamp between the TCC/stop lamp switch terminal B and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 5

5

Locate and repair the open in CKT 1540 (ORN).

Is the repair complete?

--

Go to Exterior Lights System Check

--

6

Connect a test lamp between the TCC/stop lamp switch terminal A and ground while depressing the brake pedal.

Does the test lamp light?

--

Go to Step 8

Go to Step 7

7

Adjust or replace the stoplamp switch.

Is the repair complete?

--

Go to Exterior Lights System Check

--

8

Inspect the VEH HMSL fuse in the underhood fuse block.

Is the fuse open?

--

Go to Step 9

Go to Step 10

9

Locate and repair the short to ground in CKT 1320 (LT BLU).

Is the repair complete?

--

Go to Exterior Lights System Check

--

10

  1. Disconnect the high mounted stoplamp.
  2. Connect a test lamp between CKT 1320 (LT BLU) and ground
  3. Apply the service brakes.

Does the test lamp light?

--

Go to Step 12

Go to Step 11

11

Locate and repair the open CKT 1320 (LT BLU).

Is the repair complete?

--

Go to Exterior Lights System Check

--

12

  1. Connect a test lamp between CKT 1320 (LT BLU) and CKT 1350 (BLK) at the high mounted stoplamp connector.
  2. Apply the service brake.

Does the test lamp light?

--

Go to Step 14

Go to Step 13

13

Locate and repair the open in CKT 1350 (BLK) wire.

Is the repair complete?

--

Go to Exterior Lights System Check

--

14

Inspect the bulbs in the high mounted stoplamp connector.

Are the bulbs open?

--

Go to Step 15

Go to Step 16

15

Replace the bulbs in the high mounted stoplamp. Refer to Stoplamp Bulb Replacement.

Is the repair complete?

--

Go to Exterior Lights System Check

--

16

Replace the high mounted stoplamp. Refer to High Mounted Stoplamp Replacement.

Is the repair complete?

--

Go to Exterior Lights System Check

--