Spark

Interior Backlighting Malfunction

When the headlamp switch is turned to either the PARK or HEAD position, I/P fuse block energises the park lamp relay by applying ground to the park lamp relay control circuit. With the relay energised, battery voltage is applied through the switch side of the relay and fuse F11UB. This voltage is then applied through the I/P fuse block illuminating all instrument panel cluster (IPC) lamps and components.

Observe the operation of the I/P lamps while turning the park lamps ON and OFF. The I/P lamps should turn ON and OFF as the park lamp switch is turned ON and OFF.

1. Ignition OFF, disconnect the wiring harness plug at the I/P dimmer switch.
2. Test for less than 1.0 Ωbetween ground circuit terminal 2 and ground.

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

3. Connect a test lamp between the control circuit terminal 3 and ground.
4. Ignition ON, turn the park lamps ON and OFF. The test lamp should turn ON and OFF, when switching between the commanded states.

⇒	If the test lamp is always OFF, test the control circuit for short to ground or an open/high resistance.

⇒	If the test is always ON, test the control circuit for a short circuit to B+.

5. Ignition OFF, connect the wiring harness plug at the dimmer switch and disconnect the wiring harness plug at the appropriate component.
6. Test for less than 1.0 Ω between the ground circuit terminal of the appropriate component listed below and ground:

•	Instrument panel cluster (IPC) ground circuit terminal 5.

•	Traction Control Switch ground circuit terminal 1.

•	HVAC control switch assembly ground circuit terminal 1 (X2).

•	HVAC control module ground circuit terminal 10.

•	Radio ground circuit terminal 14 (X1) (UZM), A6 (X1) (UO5), 11 (X1) (-UO5, -UZM).

•	Automatic transmission shift lock control solenoid ground circuit terminal 8.

•	Mobile telephone hands free call switch ground circuit terminal 1.

•	Mobile telephone hands free volume switch ground circuit terminal 6.

•	Hazard lamps switch ground circuit terminal 2.

•	Headlamp levelling switch ground circuit terminal 6.

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

7. Ignition ON, park lamps ON, verify that a test lamp illuminates between the control circuit terminal of the appropriate component listed below and ground:

•	Instrument panel cluster (IPC) control circuit terminal 4.

•	Traction Control Switch control circuit terminal 2.

•	HVAC control switch assembly control circuit terminal 7 (X2).

•	HVAC control module control circuit terminal 9.

•	Radio control circuit terminal 7 (X1) (UZM), A1 (X1) (UO5), 3 (X1) (-UO5, -UZM).

•	Automatic transmission shift lock control solenoid control circuit terminal 5.

•	Mobile telephone hands free call switch control circuit terminal 2.

•	Mobile telephone hands free volume switch control circuit terminal 5.

•	Hazard lamps switch control circuit terminal 3.

•	Headlamp levelling switch control circuit terminal 3.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.