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 1.4-4.5 V depending on outside lighting conditions. The body control module (BCM) monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights or automatic lamp control when the headlamp switch is in the AUTO position. In daylight conditions the BCM will command the daytime running lights ON. During low light conditions the BCM will command the low beam headlamps ON.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Exterior Lighting Systems Description and Operation (Exterior Lighting Systems)
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)
Circuit/System Verification
1. Ignition ON, observe the scan tool Ambient Light Sensor parameter. The reading should be between 1.4-4.5 V and change with ambient light changes.
• If greater or less than the specified range, refer to Ambient Light Sensor Malfunction.
2. Observe the scan tool Automatic Headlamp Disable Switch parameter while cycling the headlamp switch between the AUTOMATIC LIGHT and OFF positions. The parameter should cycle between Active and Inactive.
• If the value does not change, refer to Headlamp Switch Malfunction.
3. Observe the scan tool Headlamp ON Switch parameter while cycling the headlamp switch between the AUTOMATIC LIGHT and LOW BEAM ON position. The parameter should cycle between Active and Inactive.
• If the value does not change, refer to Headlamp Switch Malfunction.
4. Command the Left Dedicated Daytime Running Lamp and the Right Dedicated Daytime Running Lamp ON and OFF with a scan tool. The E4C daytime running lamp - left and the E4D daytime running lamp - right should turn ON and OFF while changing between the commanded states
• If the E4C daytime running lamp - left and the E4D daytime running lamp - right are always ON or always OFF, refer to Daytime Running Lamp Malfunction.
Circuit/System Testing
Ambient Light Sensor Malfunction
1. Ignition OFF, disconnect the harness connector at the B10B ambient light/sunload sensor.
2. Test for less than 30 ohm between the low reference circuit terminal 6 and ground.
• If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K33 HVAC control module.
3. Ignition ON, test for 4.8-5.2 V between the signal circuit terminal 5 and ground.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
4. If all circuits test normal, replace the B10B ambient light/sunload sensor.
Headlamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the S30 headlamp switch.
2. Ignition OFF, test for less than 30 ohm between the ground circuit terminal 6 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Park Lamps Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 6. Verify the scan tool Park Lamps Switch 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 BCM.
5. Verify the scan tool Headlamps On 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 BCM.
6. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 6. Verify the scan tool Headlamps On Switch 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 BCM.
7. Verify the scan tool Automatic Headlamps Disable Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the K9 BCM.
8. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the ground circuit terminal 6. Verify the scan tool Automatic Headlamps Disable Switch 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 BCM.
9. If all circuits test normal, test or replace the S30 headlamp switch.
Daytime Running Lamp Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the K9 BCM.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 3 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Ignition OFF, connect the X1 harness connector at the K9 BCM
4. Ignition OFF, disconnect the appropriate inline harness connector listed below:
* E4C daytime running lamp - left X111 inline harness connector
* E4D daytime running lamp - right X116 inline harness connector
5. Test for less than 30 ohm between the ground circuit terminal listed below and ground:
* Ground circuit terminal A
* Ground circuit terminal E
• If greater than the specified range, test the ground circuit for an open/high resistance.
6. Connect a test lamp between the control circuit terminal G and ground.
7. Command the appropriate Dedicated Daytime Running Lamp 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 control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 BCM.
8. If all circuits test normal, replace the daytime running lamp bulb.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Daytime Running Lamp Bulb Replacement (TT6,TT7,TT8 Passenger Side Headlamp) (Daytime Running Lamp Bulb Replacement (TT6,TT7,TT8 Passenger Side Headlamp))Daytime Running Lamp Bulb Replacement (T84, T85 Passenger Side Headlamp) (Daytime Running Lamp Bulb Replacement (T84, T85 Passenger Side Headlamp))Daytime Running Lamp Bulb Replacement (T84, T85 Driver Side Headlamp) (Daytime Running Lamp Bulb Replacement (T84, T85 Driver Side Headlamp))Daytime Running Lamp Bulb Replacement (TT6,TT7,TT8 Driver Side Headlamp) (Daytime Running Lamp Bulb Replacement (TT6,TT7,TT8 Driver Side Headlamp))
* Headlamp Switch Replacement (Service and Repair)
* Sun Load Temperature and Daytime Running Lamp Ambient Light Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning)