GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 LeSabre 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Headlamps Inoperative - High Beams

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the relay operates. Cycle between low and high positions. Repeat the cycles as necessary.

    2.

  2. Tests for supply voltage at the control side of the relay.

    3.

  3. Verifies that the headlamp switch is providing ground to the relay.

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2
  1. Turn ON the headlamps.
  2. Position the headlamp dimmer switch in the high beam position.

Do the high beam headlamps operate properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Do the low beam headlamps operate properly?

Go to Step 4

Go to Headlamps Inoperative - Low Beams

4

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the headlamps.
  3. Cycle the headlamp dimmer switch between low and high beams.

Does the HDLP HI BM relay turn ON and OFF with each cycle?

Go to Step 7

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the HDLP HI BM relay. Refer to Relay Replacement in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the control side supply voltage circuit of the HDLP HI BM relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 18

6

  1. Connect a test lamp between the headlamp high beam relay control circuit of the HDLP HI BM relay and the control side supply voltage circuit of the HDLP HI BM relay.
  2. Cycle the headlamp dimmer switch between low and high beam.

Does the test lamp turn ON and OFF with each cycle?

Go to Step 13

Go to Step 10

7
  1. Turn OFF the ignition.
  2. Disconnect the HDLP HI BM relay. Refer to Relay Replacement in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the switch side supply voltage circuit of the HDLP HI BM relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 17

8
  1. Turn OFF the ignition.
  2. Connect a 20-amp fused jumper between the HDLP HI BM relay switch side supply voltage circuit and the HDLP HI BM supply voltage circuit.
  3. Turn ON the ignition, with the engine OFF.

Did both of the high beam headlamps illuminate?

Go to Step 13

Go to Step 9

9
  1. Disconnect the inoperative high beam headlamp bulb.
  2. Connect a test lamp between the inoperative headlamp high beam supply voltage circuit and inoperative headlamp high beam ground circuit.

Does the test lamp illuminate?

Go to Step 15

Go to Step 11

10

Test the headlamp high beam relay control circuit of the HDLP HI BM relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 12

11

Test the headlamp high beam supply voltage circuit for a high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 16

12

Test the headlamp relay control circuit for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 14

13

Inspect for poor connections at the HDLP HI BM relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 19

14

Inspect for poor connections at the harness connector of the turn signal/multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

15

Inspect for poor connections at the headlamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 21

16

Repair the open or high resistance in the headlamp ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

17

Repair the high resistance or open in the switch side supply voltage circuit of the HDLP HI BM relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

18

Repair the control side supply voltage circuit of the HDLP HI BM relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

19

Replace the HDLP HI BM relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 22

--

20

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 22

--

21

Replace the headlamp bulb. Refer to Headlamp Replacement .

Did you complete the replacement?

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2