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 headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp 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, side marker, and license lamps.
Reference Information
Schematic Reference
* Headlights/Daytime Running Lights (DRL) Schematics Headlights/Daytime Running Lights (DRL) Schematics
* Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left Front
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Park Lamp Switch parameter changes between Active and Inactive while commanding the park lamps ON and OFF with the headlamp switch.
• If the parameter does not change
Refer to Park Lamp Switch Malfunction.
• If the parameter changes
3. Verify the left park lamps turn ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool.
• If the left park lamps do not turn ON and OFF
Refer to Park Lamps Malfunction.
• If the left park lamps turn ON and OFF
4. Verify the right park lamps turn ON and OFF when commanding the Right Park Lamps ON and OFF with a scan tool.
• If the right park lamps do not turn ON and OFF
Refer to Park Lamps Malfunction.
• If the right park lamps turn ON and OFF
5. Verify the license plate lamps turn ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.
• If the license plate lamps do not turn ON and OFF
Refer to License Plate Lamps Malfunction.
• If the license plate lamps turn ON and OFF
6. All OK.
Circuit/System Testing
Park Lamp Switch Malfunction
1. Ignition OFF, all doors closed, all accessories OFF, disconnect the harness connector at the S78 turn signal/multifunction switch. 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 Park Lamps Switch parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module.
2. Test for infinite resistance between the signal circuit terminal 7 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 Inactive
5. Install a 3 A fused jumper wire between the signal circuit terminal 7 and the ground circuit terminal 6.
6. Verify the scan tool Park Lamps Switch parameter is Active.
• If not Active
1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 7 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 Active
7. Test or replace the S78 turn signal/multifunction switch.
Park Lamps Malfunction
1. Ignition OFF, exterior lamps OFF, liftgate latch latched, disconnect the harness connector at the appropriate park lamp.
2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
* E4N park/turn signal lamp - left terminal G
* E2LF side marker lamp - left front terminal B
* E5S tail/stop and turn signal lamp - left terminal G
* E5J tail lamp - left lower terminal B - GMC
* E5M tail lamp - left upper terminal B - GMC
* E2LR side marker lamp - left rear terminal B - Chevrolet
* E4P park/turn signal lamp - right terminal G
* E2RF side marker lamp - right front terminal B
* E5T tail/stop and turn signal lamp - right terminal G
* E5K tail lamp - right lower terminal B - GMC
* E5N tail lamp - right upper terminal B - GMC
* E2RR side marker lamp - right rear terminal B - Chevrolet
• If 5 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 5 ohms
3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.
* E4N park/turn signal lamp - left terminal B
* E2LF side marker lamp - left front terminal A
* E5S tail/stop and turn signal lamp - left terminal B
* E5J tail lamp - left lower terminal A - GMC
* E5M tail lamp - left upper terminal A - GMC
* E2LR side marker lamp - left rear terminal A - Chevrolet
* E4P park/turn signal lamp - right terminal B
* E2RF side marker lamp - right front terminal A
* E5T tail/stop and turn signal lamp - right terminal B
* E5K tail lamp - right lower terminal A - GMC
* E5N tail lamp - right upper terminal A - GMC
* E2RR side marker lamp - right rear terminal A - Chevrolet
4. Verify the test lamp turns ON and OFF when commanding the appropriate Park Lamps ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the appropriate harness connector listed below at the K9 body control module.
* X4
* X5
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. Ignition OFF, disconnect the appropriate harness connector listed below at the K9 body control module, ignition ON.
* X4
* X5
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 park lamp.
License Plate Lamps Malfunction
1. Ignition OFF, exterior lamps OFF, liftgate latch latched, remove both E7 license plate lamp bulbs.
2. Test for less than 5 ohms between each ground circuit terminal 2 and ground.
• If 5 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 5 ohms
3. Connect a test lamp between the license plate lamp - left control circuit terminal 1 and ground, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module.
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. Ignition OFF, disconnect the X4 harness connector at the K9 body control module, 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 K9 body control module.
• If the test lamp turns ON and OFF
5. Connect a test lamp between the license plate lamp - right control circuit terminal 1 and ground, ignition ON.
6. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module.
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 turns ON and OFF
7. Test or replace the appropriate E7 license plate lamp bulb.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Rear License Plate Lamp Replacement (Equinox) Rear License Plate Lamp Replacement (Equinox)Rear License Plate Lamp Replacement (Terrain) Rear License Plate Lamp Replacement (Terrain)
* Headlamp Replacement (Equinox) Headlamp Replacement (Equinox)Headlamp Replacement (Terrain) Headlamp Replacement (Terrain)
* Tail Lamp Replacement (Equinox) Tail Lamp Replacement (Equinox)Tail Lamp Replacement (Terrain) Tail Lamp Replacement (Terrain)
* Parking and Turn Signal Lamp Bulb Replacement (Terrain) Parking and Turn Signal Lamp Bulb Replacement (Terrain)Parking and Turn Signal Lamp Bulb Replacement (Equinox) Parking and Turn Signal Lamp Bulb Replacement (Equinox)
* Tail Lamp Bulb Replacement (Equinox) Tail Lamp Bulb Replacement (Equinox)Tail Lamp Bulb Replacement (Terrain) Tail Lamp Bulb Replacement (Terrain)
* Turn Signal Multifunction Switch Replacement Turn Signal Multifunction Switch Replacement
* Front Side Marker Lamp Bulb Replacement (Terrain) Front Side Marker Lamp Bulb Replacement (Terrain)Front Side Marker Lamp Bulb Replacement (Equinox) Front Side Marker Lamp Bulb Replacement (Equinox)
* Control Module References Control Module References for BCM replacement, programming, and setup