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For 1990-2009 cars only

Headlamps - Low Beams On with Headlamp Switch Off Buick

Step

Action

Value(s)

Yes

No

1

Did you perform the Headlight System Check?

--

Go to Step 2

Go to Headlight System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the headlamps switch connector.

Do the headlights turn off?

--

Go to Step 8

Go to Step 3

3

Disconnect the headlamp dimmer switch connector C202.

Do the headlights turn off?

--

Go to Step 11

Go to Step 4

4

Disconnect the lamp control module (LCM) connector C1.

Do the headlights turn off?

--

Go to Step 7

Go to Step 5

5

Disconnect the LCM connector C2.

Do the headlights turn off?

--

Go to Step 12

Go to Step 6

6

Repair the short to battery positive voltage (B+) in the following wiring:

    • Low beams: CKT 12 (TAN)
    • High beams: CKT 11 (LT GRN)

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--

7

Test for a short to ground in CKT 103 (WHT). Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 103 OK?

--

Go to Step 10

Go to Step 14

8

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Is the repair complete?

--

Go to Headlight System Check

--

9

Connect a J 39200 digital multimeter (DMM) between the LCM connector C1 cavity A7 (PNK) and ground.

Is the voltage within the specified range?

10-15 V

Go to Step 13

Go to Step 12

10

Test for a short to ground in CKT 307 (YEL/BLK). Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 307 OK?

--

Go to Step 9

Go to Step 14

11

Replace the headlamp dimmer switch.

Is the repair complete?

--

Go to Headlight System Check

--

12

Replace the LCM.

Is the repair complete?

--

Go to Headlight System Check

--

13

Repair the short to battery positive voltage (B+) in CKT 39 (PNK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--

14

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--

Headlamps - Low Beams On with Headlamp Switch Off Oldsmobile

Step

Action

Value(s)

Yes

No

1

Did you perform the Headlight System Check?

--

Go to Step 2

Go to Headlight System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the lamp control module (LCM) connector C1.

Do the headlamps turn off?

--

Go to Step 6

Go to Step 3

3

Disconnect the LCM connector C2.

Do the headlamps turn off?

--

Go to Step 9

Go to Step 4

4

Disconnect the headlamp dimmer switch connector C202.

Do the headlamps turn off?

--

Go to Step 13

Go to Step 5

5

Repair the short to battery positive voltage (B+) in the appropriate wiring:

    • Low beams: CKT 12 (TAN)
    • High beams: CKT 11 (LT GRN)

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--

6

Test for a short to ground in CKT 103 (WHT) between the LCM and the headlamp switch. Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 103 OK?

--

Go to Step 7

Go to Step 15

7

  1. Place the headlamp switch in the OFF position.
  2. Disconnect the headlamp switch connector C202.
  3. Connect a J 39200 digital multimeter (DMM) between the headlamp switch connector C202 cavity E9 and cavity E6.

Is the resistance less than the specified value?

5 ohms

Go to Step 8

Go to Step 10

8

Replace the headlamp switch. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column-Tilt..

Is the repair complete?

--

Go to Headlight System Check

--

9

Connect the DMM between the LCM connector C2 cavity C (PNK) to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 11

Go to Step 10

10

Replace the LCM.

Is the repair complete?

--

Go to Headlight System Check

--

11

Test for a short to battery positive voltage (B+) in CKT 3 (PNK). Refer to Testing for Continuity in Wiring Systems.

Is CKT 3 OK?

--

Go to Step 12

Go to Step 15

12

Replace the ignition switch. Refer to Ignition Lock Cylinder Replacement - On Vehicle in Steering Wheel and Column-Tilt.

Is the repair complete?

--

Go to Headlight System Check

--

13

Test for a short to the battery positive voltage (B+) in CKT 1346 (LT BLU). Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 1346 OK?

--

Go to Step 14

Go to Step 15

14

Replace the headlamp dimmer switch. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column-Tilt..

Is the repair complete?

--

Go to Headlight System Check

--

15

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Headlight System Check

--