The park, tail, license, and marker lamps are turned ON when the headlamp switch is placed in the park lamp or headlamp position or anytime the headlights are requested. The park lamps are also turned ON with the front fog lamps. When the ignition switch is in the ON position, the instrument panel module (IPM) provides ground to the controlled voltage circuit of the park lamp relay coil. The underhood fuse block supplies battery voltage to the switch contacts of the park lamp relay. When the headlamp switch is placed in the park lamp or headlamp positions, the park lamp switch ON signal circuit is provided ground at G200. In response to this signal, the IPM provides ground to the control circuit of the park lamp relay coil, which energizes the relay coil. When the park lamp relay coil is energized, the relay switch contacts close causing current to flow from the park lamp relay to the LIC/Dimming fuse, LT PARK fuse, and to the RT PARK fuse. From these fuses, current flows to the park lamps, license lamps, side marker lamps, and tail lamps. The front park lamps and side marker lamps are grounded at G104. The tail lamps and rear sidemarker lamps are grounded at G401 and G402. The LIC/dimming fuse supplies battery positive voltage to the license lamps and IPM instrument panel lamp fuse supply voltage circuit for interior lamps dimming. The license lamps are grounded at G402.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Park Lamp Switch parameter while cycling the park lamp switch between the ON and OFF positions. The parameter should change between On and Off.

Park Lamp Switch Malfunction

1. Ignition OFF, disconnect the X3 harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal K.

⇒	If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Park Lamp Switch parameter is Off.

⇒	If not the specified value, test the signal circuit terminal M for a short to ground. If the circuit tests normal, replace the IPM.

4. Install a 3A fused jumper wire between the signal circuit terminal M and ground. Verify the scan tool Park Lamp Switch parameter is On.

⇒	If not the specified value, test the signal circuit terminal M for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.

5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Park, License, and/or Tail Lamps Malfunction

1. Ignition OFF, remove the fuse of the inoperative park/marker/license lamps and inspect.

⇒	If the fuse is OPEN, test the control circuit of the blown fuse for a short to ground.

2. Ignition OFF, connect the fuse and disconnect the park lamp relay.
3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R33 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

4. Verify that a test lamp illuminates between the B+ circuit terminal R32 and ground.

⇒	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 R33 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.

5. Verify that a test lamp illuminates between the B+ circuit terminal R31 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

6. Disconnect the harness connector at the inoperative park/marker/license lamp.
7. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

8. Connect the harness connector at the inoperative park/marker/license lamp.
9. Connect a 30A fused jumper wire between the B+ circuit terminal R32 and the control circuit terminal R33. Verify the park/marker/license lamps are activated.

⇒	If the park/marker/license lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative park/marker/license lamp.

10. Connect a test lamp between the B+ circuit terminal R31 and the control circuit terminal R34.
11. 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 the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM.

⇒	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 IPM.

12. If all circuits test normal, test or replace the park lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.