Park, License, and/or Tail Lamps Malfunction
Park, License, and/or Tail 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
When the turn signal/multifunction switch is placed in the HEAD or PARK position, ground is applied to the park lamps ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.
Reference Information
Schematic Reference
* Exterior Lights Schematics Exterior Lights Schematics
* Body Control System Schematics [1][2]Body Control Systems
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
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 for scan tool information
Circuit/System Verification
1. Vehicle in Service Mode, observe the scan tool Park Lamps Switch parameter while turning the turn signal/multifunction switch between the OFF and PARK positions. The parameter should change between Active and Inactive.
• If the parameter does not change between the commanded states, refer to Park Lamp Switch Malfunction.
2. Command the Left Front Park Lamp ON and OFF with a scan tool. The left front park lamp should turn ON and OFF when changing between the commanded states.
• If the left front park lamp does not turn ON and OFF when commanded, refer to Park Lamps Malfunction.
3. Command the Left Rear Park Lamp ON and OFF with a scan tool. The left rear park lamp should turn ON and OFF when changing between the commanded states.
• If the left rear park lamp does not turn ON and OFF when commanded, refer to Park Lamps Malfunction.
4. Command the Right Front Park Lamp ON and OFF with a scan tool. The right front park lamp should turn ON and OFF when changing between the commanded states.
• If the right front park lamp does not turn ON and OFF when commanded, refer to Park Lamps Malfunction.
5. Command the Right Rear Park Lamp ON and OFF with a scan tool. The right rear park lamp should turn ON and OFF when changing between the commanded states.
• If the right rear park lamp does not turn ON and OFF when commanded, refer to Park Lamps Malfunction.
6. Command the License Plate Lamps ON and OFF with a scan tool. The license plate lamps should turn ON and OFF when changing between the commanded states.
• If the license plate lamps do not turn ON and OFF when commanded, refer to License Plate Lamps Malfunction.
Circuit/System Testing
Park Lamp Switch Malfunction
1. Vehicle OFF, disconnect the harness connector at the S78 turn signal/multifunction switch.
2. Vehicle OFF, all doors closed, all accessories OFF, and wait 2 minutes. Test for less than 10 ohm between the ground circuit terminal 6 and ground.
• If greater then the specified range, test the ground circuit for an open/high resistance.
3. Vehicle in Service Mode, verify the scan tool Park Lamps Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 7 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 7 and ground. Verify the scan tool Park Lamps 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 BCM.
5. If all circuits test normal, replace the S78 turn signal/multifunction switch.
Park Lamps Malfunction
1. Vehicle OFF, disconnect the harness connector at the inoperative E4 park lamp.
2. Vehicle OFF, exterior lamps OFF, test for less than 5 ohm between the appropriate ground circuit terminal listed below and ground:
* E4N park/turn signal lamp - left - terminal 1
* E4P park/turn signal lamp - right - terminal 1
* E42L tail lamp assembly - left - terminal 4
* E42R tail lamp assembly - right - terminal 4
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the appropriate control circuit terminal listed below and ground:
* E4N park/turn signal lamp - left - terminal 2
* E4P park/turn signal lamp - right - terminal 2
* E42L tail lamp assembly - left - terminal 2
* E42R tail lamp assembly - right - terminal 2
4. Vehicle in Service Mode, command the appropriate Park 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 circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, replace the inoperative E4 park lamp.
License Plate Lamps Malfunction
1. Vehicle OFF, disconnect the harness connector at the E7L license plate lamp - left and E7R license plate lamp - right.
2. Vehicle OFF, exterior lamps OFF, test for less than 5 ohm between each ground circuit terminal 2 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the E7L license plate lamp - left control circuit terminal 1 and ground.
4. Vehicle in Service Mode, command the License Plate Lamps 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 circuit tests normal, replace the K9 BCM.
5. Vehicle OFF, connect a test lamp between the E7R license plate lamp - right control circuit terminal 1 and ground.
6. Vehicle in Service Mode, command the License Plate Lamps 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
7. If all circuits test normal, replace the inoperative E7 license plate lamp bulb.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Rear License Plate Lamp Replacement Rear License Plate Lamp Replacement
* Tail Lamp Replacement Tail Lamp Replacement
* Turn Signal Multifunction Switch Replacement Turn Signal Multifunction Switch Replacement
* Tail Lamp Replacement Tail Lamp Replacement
* Control Module References Programming and Relearning for BCM replacement, setup, and programming