Chevrolet Trax: Daytime running lamps malfunction

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

Daytime Running Lamps - with TR6

The ambient light sensor is used to monitor outside lighting conditions. The body control module (BCM) provides a low reference ground and 5-volt reference signal to the ambient light sensor. Depending on outside lighting conditions, the ambient light sensor provides a voltage signal to the BCM that will vary between 0.2 and 4.9 volts. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic headlamp system control when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the low beam headlamps (DRLs) ON by applying low voltage to the low beam headlamp control circuits illuminating the low beam headlamps at reduced intensity. Any function or condition that turns on the headlamps will cancel DRL operation.

Daytime Running Lamps - with T4A

The ambient light sensor is used to monitor outside lighting conditions. The body control module (BCM) provides a low reference ground and 5-volt reference signal to the ambient light sensor. Depending on outside lighting conditions, the ambient light sensor provides a voltage signal to the BCM that will vary between 0.2 and 4.9 volts. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic headlamp system control when the headlamp switch is in the AUTO position. In daylight conditions, the BCM responds by applying battery voltage to the left and right daytime running lamp relay control circuits which energizes both daytime running lamp relays. With the daytime running lamp relays energized, the switch contacts close allowing battery voltage to flow to the daytime running lamp control circuits illuminating the left and right daytime running lamp.

Reference Information

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics (Encore) , Headlights/Daytime Running Lights (DRL) Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

• Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify the low beam headlamps turn on & off when commanding the Low Beam Headlamps ON and OFF with a scan tool.

• If the low beam headlamps do not turn ON and OFF

Refer to Headlamps Malfunction.

• If the low beam headlamps turn ON and OFF

3. Ignition ON, park brake released.
4. Verify the scan tool BCM Park Brake Status parameter displays released.

• If the park brake status parameter does not display released

Refer to Brake Warning Indicator Malfunction (Without J41) , Brake Warning Indicator Malfunction (With J41)

• If the parameter displays released

5. Refer to Circuit/System Testing.

Circuit/System Testing

Daytime Running Lamps Malfunction - with TR6

1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the B10 Ambient Light Sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 15 ohms between the ground circuit terminal 6 and ground.

• If 15 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 15 ohms

3. Ignition ON.
4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V.

• If 4.65 V or less

1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit terminal 5 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K9 Body Control Module.
• If greater than 4.65 V

5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the ground circuit terminal 6.
6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V.

• If 0.196 V or greater

1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 5 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 Body Control Module.
• If less than 0.196 V

7. Test or replace the B10 Ambient Light Sensor.

Daytime Running Lamps Malfunction - with T4A

1. Ignition OFF, exterior lamps OFF, remove the appropriate E4 Daytime Running Lamp bulb.
2. Test for less than 15 ohms between the ground circuit at the socket terminal and ground.

• If 15 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 15 ohms

3. Install the E4 Daytime Running Lamp Bulb.
4. Disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
5. Test for less than 15 ohms between the appropriate ground circuit terminal listed below and ground.

• Terminal G3 - left daytime running lamp
• Terminal D9 - right daytime running lamp
• If 15 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 15 ohms

6. Connect the X2 harness connector at the X50A Fuse Block - Underhood.
7. Disconnect the X1 harness connector at the X50A Fuse Block - Underhood.
8. Connect a 3 A fused jumper between the appropriate control circuit terminal listed below and B+.

• Terminal H1 - left daytime running lamp
• Terminal G2- left daytime running lamp

9. Verify the appropriate E4 Daytime Running Lamp illuminates.

• If the daytime running lamp does not illuminate

1. Ignition OFF, remove the appropriate E4 Daytime Running Lamp.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the appropriate E4 Daytime Running Lamp.
• If the daytime running lamp illuminates

10. Ignition OFF, connect the X1 harness connector at the X50A Fuse Block - Underhood.
11. Disconnect the X7 harness connector at the K9 Body Control Module, ignition ON.
12. Verify a test lamp does not illuminate between the control circuit terminal 8 and ground.

• If the test lamp illuminates

1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, ignition ON.
2. Test for less than 1 V between the control circuit terminal and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the X50A Fuse Block - Underhood.
• If the test lamp does not illuminate

13. Ignition OFF, connect a 3 A fused jumper between the control circuit terminal 8 and B+, ignition ON.
14. Verify both daytime running lamps illuminate.

• If the daytime running lamps do not illuminate

1. Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the X50A Fuse Block - Underhood.
• If the daytime running lamps illuminate

15. Test or replace the K9 Body Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Sun Load Temperature Sensor Replacement
• Front Compartment Fuse Block Replacement
• Control Module References for BCM replacement, programming, and setup

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