GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 GL7 (Export) 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlamp Low or High Beams Always On

Step

Action

Yes

No

1

Did you perform the Lighting System Diagnostic System check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2
  1. Place the headlamp and IP lamp dimmer switch in the OFF position.
  2. Place the headlamp dimmer switch in the LOW position.
  3. Place the headlamp dimmer switch in the HIGH position.

Do both the low beam headlamps and high beam headlamps illuminate?

Go to Step 4

Go to Step 3

3

Do the low beam headlamps illuminate?

Go to Step 5

Go to Step 11

4
  1. Disconnect the headlamp and IP lamp dimmer switch.
  2. Place the headlamp dimmer switch in the LOW position.
  3. Place the headlamp dimmer switch in the HIGH position.

Do both the low beam headlamps and high beam headlamps illuminate?

Go to Step 10

Go to Step 18

5

Remove the LH Head LP LOW Fuse.

Does the LH low beam headlamps illuminate?

Go to Step 6

Go to Step 7

6

Repair the short to B+ in CKT 712 between the fuse block and the LH headlamp.

Is the repair complete?

Go to Step 19

--

7

Remove the RH Head LP LOW Fuse.

Does the RH low beam headlamps illuminate?

Go to Step 8

Go to Step 9

8

Repair the short to B+ in CKT 312 between the fuse block and the RH headlamp.

Is the repair complete?

Go to Step 19

--

9

Repair the short to B+ in CKT 12 between the fuse block and the Headlamp dimmer switch.

Is the repair complete?

Go to Step 19

--

10

Repair the short to B+ in CKT 10 between the fuse block and the Headlamp dimmer switch.

Is the repair complete?

Go to Step 19

--

11

Disconnect the headlamp dimmer switch

Does the high beam headlamps illuminate?

Go to Step 12

Go to Step 17

12

Remove the LH Head LP HIGH Fuse.

Does the LH high beam headlamps illuminate?

Go to Step 13

Go to Step 14

13

Repair the short to B+ in CKT 711 between the fuse block and the LH headlamp.

Is the repair complete?

Go to Step 19

--

14

Remove the RH Head LP HIGH Fuse.

Does the RH high beam headlamps illuminate?

Go to Step 15

Go to Step 16

15

Repair the short to B+ in CKT 311 between the fuse block and the RH headlamp.

Is the repair complete?

Go to Step 19

--

16

Repair the short to B+ in CKT 11 between the fuse block and the Headlamp dimmer switch.

Is the repair complete?

Go to Step 19

--

17
  1. Locate a short to B+ in CKT 11 between C201 and the headlamp dimmer switch.
  2. Replace the headlamp dimmer switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel Column -Tilt.

Is the repair complete?

Go to Step 19

--

18

Replace the headlamp and IP dimmer switch. Refer to Headlamp Switch Replacement .

Is the repair complete?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2