Cruze

Headlamps Malfunction

Dipped Beam

The vehicle headlamps are controlled by the body control module (BCM) based on inputs from the headlamp switch and the indicator/multifunction switch. The headlamp switch has four positions: Off, Auto, Parking light, and Dipped beam. For vehicles equipped with ambient light sensor the default headlamp switch position is Auto, in which the BCM uses the ambient light sensor to determine when headlamps are needed. When in the Off position, the headlamp switch grounds the headlamp switch headlamps OFF signal circuit, prompting the BCM to turn off the headlamps. The Park position of the headlamp switch will only illuminate the vehicle parking lamps. The Headlamp position of the headlamp switch will illuminate both the parking lamps, as well as the headlamps. With the headlamp switch in the Headlamp position, the headlamp switch headlamps on signal circuit is grounded, prompting the BCM to turn on the headlamps, regardless of other factors such as ambient light.

Main Beam

The headlamp main beams are controlled through the flash to pass switch and the headlamp dimmer switch, both located in the indicator/multifunction switch. The flash to pass switch is a momentary type switch, designed to illuminate the main beams as long as the switch is held. With the switch closed, the flash to pass switch signal circuit is grounded, prompting the BCM to turn on the main beam lamps. The headlamp dimmer switch allows the operator to select between full time high or dipped beam operation. Unlike the flash to pass switch, it is not a momentary switch. When the headlamp dimmer switch is in the main beam position, the headlamp dimmer switch main beam signal circuit is grounded. This prompts the BCM to turn on the main beam lamps.

Schematic Reference

Headlamps/Daytime Running Lamps (DRL) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool Headlamp On Switch parameter while cycling the headlamp switch between the ON and OFF positions. The parameter should cycle between Active and Inactive.

⇒	If the parameter does not cycle between the specified values, refer to Headlamp Switch Malfunction.

2. With the dipped beams ON, observe the scan tool Headlamps Flash Switch parameter while pulling and releasing the indicator/multifunction switch. The parameter should cycle between Active and Inactive.

⇒	If the parameter does not cycle between the specified values, refer to Indicator/Multifunction Switch Malfunction.

3. With the dipped beams ON, observe the scan tool Main Beam Select Switch parameter while switching the Indicator/Multifunction Switch between the dipped and main beam positions. The parameter should cycle between Active and Inactive.

⇒	If the parameter does not cycle between the specified values, refer to Indicator/Multifunction Switch Malfunction.

4. Command the Dipped Beams ON and OFF with a scan tool. Verify the dipped beam headlamps turn ON and OFF.

⇒	If the dipped beam headlamps do not cycle between the commanded states, refer to Dipped Beam Headlamp Malfunction.

5. Command the High Beams ON and OFF with a scan tool. Verify the dipped beam headlamps turn ON and OFF.

⇒	If the main beam headlamps do not cycle between the commanded states, refer to Main Beam Headlamp Malfunction.

Headlamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
2. Verify that a test lamp illuminates between the ground circuit terminal 6 and B+.

⇒	If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the signal circuit terminals listed below and ground:

•	Headlamp switch dipped beams ON signal terminal 4

•	Park lamp switch ON signal terminal 3

•	Headlamp switch OFF signal terminal 5

⇒	If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

4. Install a 3 A fused jumper wire between the park lamp ON signal circuit terminal 3 and ground. Verify the scan tool Parklamp Switch parameter changes from Inactive to Active.

⇒	If always Inactive, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If always Active, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

5. Install a 3 A fused jumper wire between the dipped beams ON signal circuit terminal 4 and ground. Verify the scan tool Headlamp On Switch parameter changes from Inactive to Active.

⇒	If always Inactive, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If always Active, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

6. Remove the jumper wire. Install a 3 A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Automatic Headlamp Disable Switch parameter is briefly Active.

⇒	If always Inactive, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If always Active, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

7. If all circuits test normal, replace the S30 Headlamp Switch.

Indicator/Multifunction Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the S78 Indicator/Multifunction Switch.
2. Disconnect the negative terminal of the C1 Battery.
3. Ignition OFF, test for less than 5 Ω between the ground circuit terminal 3 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

4. Reconnect the negative terminal to the C1 Battery.
5. Ignition ON, verify the scan tool Headlamps Flash Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

6. Verify the scan tool High Beam Select Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

7. Install a 3 A fused jumper wire between the signal circuit terminal 4 and ground. Verify the scan tool Headlamps Flash Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

8. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool High Beam Select Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

9. If all circuits test normal, test or replace the S78 Indicator/Multifunction Switch.

Low Beam Headlamp Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate head lamp.
2. Test for less than 5 Ω between the appropriate headlamp ground circuit harness connector listed below and ground.

•	E13L Headlamp Assembly - Left ground circuit harness connector terminal 3

•	E13R Headlamp Assembly - Right ground circuit harness connector terminal 3

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the appropriate head lamp control circuit harness connector listed below and ground.

•	E13L Headlamp Assembly - Left signal circuit harness connector terminal 2

•	E13R Headlamp Assembly - Right signal circuit harness connector terminal 2

4. Command the appropriate Headlamp Low Beam test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the Signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 Body Control Module.

5. If all the circuits test normal, replace the appropriate headlamp.

High Beam Headlamp Malfunction

1. Ignition OFF, disconnect the appropriate harness connector at headlamp lamp listed below:

•	E13L Headlamp Assembly - Left

•	E13R Headlamp Assembly - Right

2. Disconnect the negative terminal of the C1 Battery.
3. Test for less than 5 Ω between the appropriate headlamp ground circuit harness connector terminal 3 and ground.

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

4. Reconnect the negative terminal to the C1 Battery.
5. Remove the appropriate fuse listed below:

•	F38UA Left Main Beam

•	F37UA Right Main Beam

6. Verify that the headlamp does not illuminate.

⇒	If the headlamp does illuminate, test the signal circuit for a short to voltage.

7. Install a 10 A fused jumper wire between appropriate fuse output contact and B+ Verify that the appropriate main beam illuminates.

⇒	If the main beam lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate bulb.

8. Disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
9. Connect a test lamp between the signal circuit terminal 58 (X2) and B+.
10. Ignition ON, switch the main beam lamps ON and OFF by using the S78 Indicator/Multifunction Switch. The test lamp should go ON and OFF.

⇒	If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

11. If all circuits test normal, replace the X50A Fuse Block - Underhood.

Static Test - Headlamp Switch

1. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
2. Test for infinite resistance between the signal terminal 5 and the ground terminal 6 with the switch in the Auto position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

3. Test for infinite resistance between the signal terminal 4 and the ground terminal 6 with the switch in the Auto position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

4. Test for infinite resistance between the signal terminal 3 and the ground terminal 6 with the switch in the Auto position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

5. Test for less than 2 Ω between the signal terminal 5 and the ground terminal 6 with the switch in the Off position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

6. Test for less than 2 Ω between the signal terminal 4 and the ground terminal 6 with the switch in the Dipped beam position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

7. Test for less than 2 Ω between the signal terminal 3 and the ground terminal 6 with the switch in the Park Lamp position.

⇒	If not the specified value, replace the S30 Headlamp Switch.

Indicator/Multifunction Switch

1. Ignition OFF, disconnect the harness at the S78 Indicator/Multifunction Switch.
2. Test for infinite resistance between the signal terminal 4 and the ground terminal 3 with the flash to pass switch in the open position.

⇒	If not the specified value, replace the S78 Indicator/Multifunction Switch.

3. Test for infinite resistance between the signal terminal 2 and the ground terminal 3 with the headlamp dimmer switch in the low beam position.

⇒	If not the specified value, replace the S78 Indicator/Multifunction Switch.

4. Test for less than 2 Ω between the signal terminal 4 and the ground terminal 3 with the flash to pass switch in the closed position.

⇒	If not the specified value, replace the S78 Indicator/Multifunction Switch.

5. Test for less than 2 Ω between the signal terminal 2 and the ground terminal 3 with the headlamp dimmer switch in the main beam position.

⇒	If not the specified value, replace the S78 Indicator/Multifunction Switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.