GM Service Manual Online
For 1990-2009 cars only

Headlamps Inoperative - One Lamp Domestic

Step

Action

Value(s)

Yes

No

1

Was the entire Headlight System Check performed?

--

Go to Step 2

Go to Headlight System Check

2

Check for an open in the appropriate fuse:

    • LH low beam: HDLOBML Fuse
    • RH low beam: HDLOBMR Fuse
    • LH high beam: HDHIBML Fuse
    • RH high beam: HDHIBMR Fuse

Is the suspect fuse OK?

--

Go to Step 3

Go to Step 7

3

Check that the bulb connections are clean and tight.

Were the bulb connections OK?

--

Go to Step 4

Go to Step 9

4

  1. Place the headlamp switch in the ON position.
  2. Disconnect the suspect headlamp connector.
  3. Connect a DMM from the suspect headlamp connector cavity A to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 5

Go to Step 16

5

Connect a DMM from the suspect headlamp connector cavity A to cavity B.

Is the voltage within the specified range?

10-15 V

Go to Step 6

Go to Step 10

6

Replace the inoperative headlamp. Refer to Headlamp Replacement .

Is the headlamp replacement complete?

--

Go to Headlight System Check

--

7

Repair the short to ground in the appropriate wiring:

    • LH low beam: CKT 712 (YEL)
    • RH low beam: CKT 312 (YEL) or (TAN/WHT)
    • LH high beam: CKT 711 (DK GRN/WHT)
    • RH high beam: CKT 311 (DK GRN/WHT) or (LT GRN/BLK)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 8

--

8

Replace the inoperative fuse:

    • LH low beam: HDLOBML Fuse
    • RH low beam: HDLOBMR Fuse
    • LH high beam: HDHIBML Fuse
    • RH high beam: HDHIBMR Fuse

Refer to Wiring Repairs in Wiring Systems.

Is the headlamp replacement complete?

--

Go to Headlight System Check

--

9

Repair the bulb connections.

Is the repair complete?

--

Go to Headlight System Check

--

10

Was the LH high beam headlamp the inoperative headlamp?

--

Go to Step 12

Go to Step 11

11

Repair the open between ground G401 and the suspect headlamp in the appropriate wiring:

    • LH low beam: CKT 1050 (BLK)
    • RH low beam: CKT 1050 (BLK)
    • RH high beam: CKT 1050 (BLK) or (PNK)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Headlight System Check

--

12

Do the DRL function properly?

--

Go to Step 13

Go to Daytime Running Lamps (DRL) Headlamps Inoperative

13

Backprobe the underhood junction block connector C1 with a DMM from cavity F7 (DK GRN/WHT) to cavity F11 (BLK).

Is the voltage within the specified range?

10-15 V

Go to Step 14

Go to Step 15

14

Replace the DRL relay in the underhood junction block. Refer to Wiring Repairs in Wiring Systems.

Does the headlamp now operate properly?

--

Go to Headlight System Check

Go to Step 17

15

Repair the open in CKT 250 (BLK) between the underhood junction block and G104. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Headlight System Check

--

16

Repair the open between the underhood junction block and the suspect headlamp in the appropriate wiring:

    • LH low beam: CKT 712 (YEL)
    • RH low beam: CKT 312 (YEL) or (TAN/WHT)
    • LH high beam: CKT 711 (DK GRN/WHT)
    • RH high beam: CKT 311 (DK GRN/WHT) or (LT GRN/BLK)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Headlight System Check

--

17

Replace the underhood junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical.

Is the underhood junction block replacement complete?

--

Go to Headlight System Check

--

Headlamps Inoperative - One Lamp Export

Step

Action

Value(s)

Yes

No

1

Was the entire Headlight System Check performed?

--

Go to Step 2

Go to Headlight System Check

2

Check for an open in the appropriate fuse:

    • LH low beam: HDLOBML Fuse
    • RH low beam: HDLOBMR Fuse
    • LH high beam: HDHIBML Fuse
    • RH high beam: HDHIBMR Fuse

Is the suspect fuse OK?

--

Go to Step 3

Go to Step 7

3

Check that the bulb connections are clean and tight.

Were the bulb connections OK?

--

Go to Step 4

Go to Step 9

4

  1. Place the headlamp switch in the ON position.
  2. Disconnect the suspect headlamp connector.
  3. Connect a DMM from the suspect headlamp connector cavity A to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 5

Go to Step 10

5

Connect a DMM from the suspect headlamp connector cavity A to cavity B.

Is the voltage within the specified range?

10-15 V

Go to Step 6

Go to Step 11

6

Replace the inoperative headlamp. Refer to Headlamp Replacement .

Is the headlamp replacement complete?

--

Go to Headlight System Check

--

7

Repair the short to ground in the appropriate wiring:

    • LH low beam: CKT 712 (YEL)
    • RH low beam: CKT 312 (YEL) or (TAN/WHT)
    • LH high beam: CKT 711 (DK GRN/WHT)
    • RH high beam: CKT 311 (DK GRN/BLK) or (LT GRN/BLK)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 8

--

8

Replace the inoperative fuse.

    • LH low beam: HDLOBML Fuse
    • RH low beam: HDLOBMR Fuse
    • LH high beam: HDHIBML Fuse
    • RH high beam: HDHIBMR Fuse

Refer to Wiring Repairs in Wiring Systems.

Is the fuse replacement complete?

--

Go to Headlight System Check

--

9

Repair the bulb connections.

Is the repair complete?

--

Go to Headlight System Check

--

10

Repair the open between the underhood junction block and the suspect headlamp in the appropriate wiring:

    • LH low beam: CKT 712 (YEL)
    • RH low beam: CKT 312 (YEL) or (TAN/WHT)
    • LH high beam: CKT 711 (DK GRN/WHT)
    • RH high beam: CKT 311 (DK GRN/BLK) or (LT GRN/BLK)

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Headlight System Check

--

11

Repair the open in the appropriate wiring:

    • LH low beam: CKT 1050 (BLK) between the headlamp and S100.
    • RH low beam: CKT 1050 (BLK) between the headlamp and S102.
    • LH high beam: CKT 250 (BLK) between the headlamp and G104.
    • RH high bean: CKT 1050 (BLK) between the headlamp and S114.

Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Headlight System Check

--