GM Service Manual Online
For 1990-2009 cars only

Headlamps Inoperative - High Beams Domestic, Europe, and Japan

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the headlamp switch to the ON position.
  2. Push the headlamp dimmer switch away from the driver.
  3. Backprobe the underhood fuse block connector C2 with a DMM from cavity D1 (DK GRN) to cavity C2 (BLK/WHT).

Is the voltage within the specified range?

10-15 V

Go to Step 3

Go to Step 5

3

Replace the HDLP HI BM relay in the underhood fuse block.

Do both hi beam headlamps now operate properly?

--

Go to Step 8

Go to Step 4

4

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Is the underhood fuse block replacement complete?

--

Go to Step 8

--

5

  1. Remove the HDLP HI BM relay from the underhood fuse block.
  2. Disconnect the headlamp dimmer switch connector C202.
  3. Backprobe the underhood fuse block connector C2 with a DMM from cavity C2 (BLK/WHT) to the headlamp dimmer switch connector C202 cavity B10 (BLK/WHT).

Is the resistance less than the specified value?

0.5 ohms

Go to Step 6

Go to Step 7

6

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

Is the headlamp dimmer switch replacement complete?

--

Go to Step 8

--

7

Repair the open in CKT 1969 (BLK/WHT) between the underhood fuse block and the headlamp dimmer switch. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK.

Go to Step 2

Headlamps Inoperative - High Beams Norway and Sweden

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the headlamp switch to the ON position.
  2. Push the headlamp dimmer switch away from the driver.
  3. Backprobe the underhood fuse block connector C2 with a DMM from cavity D1 (DK GRN) to cavity C2 (BLK/WHT).

Is the voltage within the specified range?

10-15 V

Go to Step 3

Go to Step 5

3

Replace the HDLP HI BM relay in the underhood fuse block.

Do both hi beam headlamps now operate properly?

--

Go to Step 10

Go to Step 4

4

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Is the underhood fuse block replacement complete?

--

Go to Step 10

--

5

Backprobe the underhood fuse block connector C2 with a DMM from cavity D1 (DK GRN) to the headlamp dimmer switch connector C202 cavity B9 (PNK/WHT).

Is the voltage within the specified range?

10-15 V

Go to Step 6

Go to Step 9

6

Backprobe the underhood fuse block connector C2 with a DMM from cavity D1 (DK GRN) to the headlamp dimmer switch connector C202 cavity B10 (BLK/WHT).

Is the voltage within the specified range?

10-15 V

Go to Step 7

Go to Step 8

7

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

Is the headlamp dimmer switch replacement complete?

--

Go to Step 10

--

8

Repair the open in CKT 1969 (BLK/WHT) between the underhood fuse block and the headlamp dimmer switch. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 10

--

9

Repair the open in CKT 1970 (PNK/WHT) between the underhood fuse block and the headlamp dimmer switch. Refer to Wiring Repairs in Wiring Systems.

Is the circuit repair complete?

--

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK.

Go to Step 2