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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Park Lamp Relay Control | 1 | 1 | B2585 00 | -- |
Park Lamp Switch ON Signal | 2 | 2 | 2 | -- |
License Lamp Supply Voltage | 1 | 1 | 1 | -- |
Park Lamp Voltage Supply | 1 | 1 | 1 | -- |
License Lamp Ground | -- | 1 | 1 | -- |
Park Lamps - LF Ground | -- | 1 | 1 | -- |
Park Lamps - RF Ground | -- | 1 | 1 | -- |
Tail/Stop and Turn Signal Lamps - LR Ground | -- | 1 | 1 | -- |
Tail/Stop and Turn Signal Lamps - RR Ground | -- | 1 | 1 | -- |
Turn Signal/Multifunction Switch Ground | -- | 2 | 2 | -- |
| ||||
Circuit/System Description
Battery positive voltage is applied at all times to both the coil and switched sides of the PARK LAMP relay. Ground is applied from G200 to the multifunction switch at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp relay control circuit. This energizes the PARK LAMP relay and applies battery positive voltage to all of the park, tail, license, and marker lamps. For more detailed information concerning park lamp operation refer to Exterior Lighting Systems Description and Operation .
Reference Information
Schematic Reference
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe the scan tool park lamp switch parameter while cycling the park lamp switch between the ON and OFF positions. The readings should toggle between ACTIVE and INACTIVE.
| ⇒ | If the readings do not change between the commanded states, refer to Park Lamp Switch Malfunction. |
Circuit/System Testing
Park Lamp Switch Malfunction
- Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
- Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal K.
- Ignition ON, verify the scan tool park lamp switch parameter is INACTIVE.
- Install a 3A fused jumper wire between the signal circuit terminal M and ground. Verify the scan tool park lamp switch parameter is ACTIVE.
- If all circuits test normal, test or replace the turn signal multifunction switch.
| ⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal M for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
Park, License, and/or Tail Lamps Malfunction
- Ignition OFF, remove the fuse of the inoperative park/marker lamps and inspect.
- Ignition OFF, disconnect the park lamp relay.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R23 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal R25 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal R22 and ground.
- Disconnect the harness connector at the inoperative park/marker lamp.
- Ignition OFF, exterior lamps OFF, test for less than 2.0 ohms of resistance between the inoperative park/marker lamp ground circuit and ground
- Connect the harness connector at the inoperative park/marker lamp.
- Connect a 10A fused jumper wire between the B+ circuit terminal R22 and the control circuit terminal R23. Verify the park/marker lamps are activated.
- Connect a test lamp between the B+ circuit terminal R25 and the control circuit terminal R21.
- Command the park lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the park lamp relay.
| ⇒ | If the fuse is OPEN, test the voltage supply circuit of the blown fuse for a short to ground. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R23 for a short to ground. If the circuit tests normal, test or replace the park lamp relay. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the park lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative park lamp. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
