Daytime Running Lamps Malfunction
Daytime Running Lamps Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor and the HVAC control module provides a low reference ground. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or the automatic headlamp system when the headlamp switch is in the AUTO position. In daylight conditions, the BCM will command the DRLs ON by applying voltage to the left and right DRL control circuits illuminating the DRLs. Any function or condition that turns on the headlamps will cancel DRL operation.
Diagnostic Aids
The daytime running lamps will only operate in daylight conditions with the vehicle ON and in any transmission gear except PARK.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
Exterior Lights Schematics Exterior Lights Schematics
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Vehicle ON.
2. Verify the left daytime running lamp turns ON and OFF when commanding the Left Dedicated Daytime Running Lamp ON and OFF with a scan tool.
• If the left daytime running lamp does not turn ON and OFF
Refer to Daytime Running Lamp Malfunction.
• If the left daytime running lamp turns ON and OFF
3. Verify the right daytime running lamp turns ON and OFF when commanding the Right Dedicated Daytime Running Lamp ON and OFF with a scan tool.
• If the right daytime running lamp does not turn ON and OFF
Refer to Daytime Running Lamp Malfunction.
• If the right daytime running lamp turns ON and OFF
Refer to Ambient Light Sensor Malfunction.
Circuit/System Testing
Ambient Light Sensor Malfunction
1. Vehicle OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the B10B ambient light/sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 15 ohms between the low reference circuit terminal 6 and ground.
• If 15 ohms or greater
1. Vehicle OFF, disconnect the X1 harness connector at the K33 HVAC control module, vehicle in Service Mode.
2. Test for less than 1 V between the low reference circuit terminal 6 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 low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K33 HVAC control module.
• If less than 15 ohms
3. Vehicle in Service Mode.
4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V.
• If 4.65 V or less
1. Vehicle 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 low reference 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. Vehicle OFF, disconnect the X2 harness connector at the K9 body control module, vehicle in Service Mode.
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 Lamp Malfunction
1. Vehicle OFF, exterior lamps OFF, disconnect the harness connector at the inoperative E13 headlamp.
2. Test for less than 5 ohms between the ground circuit terminal 4 and ground.
• If 5 ohms or greater
1. Vehicle 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 5 ohms
3. Connect a test lamp between the control circuit terminal 2 and ground, vehicle ON.
4. Verify the test lamp turns ON and OFF when commanding the appropriate Dedicated Daytime Running Lamp ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module.
* X5 - left daytime running lamp
* X7 - right 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 K9 body control module.
• If the test lamp is always ON
1. Vehicle OFF, disconnect the appropriate harness connector listed below at the K9 body control module, vehicle ON.
* X5 - left daytime running lamp
* X7 - right daytime running lamp
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 K9 body control module.
• If the test lamp turns ON and OFF
5. Test or replace the appropriate E4 daytime running lamp.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Headlamp Replacement Removal and Replacement
* Headlamp Bulb Replacement Service and Repair
* Sun Load Temperature and Headlamp Automatic Control Ambient Light Sensor Replacement Service and Repair
* Control Module References Programming and Relearning for BCM or HVAC control module replacement, programming, and setup