Interior Light System: Inspection: Trouble Symptom

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

The spot map light, room light or trunk room light does not illuminate.

Wiring diagram:

Interior light system Ref. to WIRING SYSTEM>INTERIOR LIGHT SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

NOTE:

Operate the appropriate switch according to the inspection condition.

CHECK INTERIOR LIGHT ILLUMINATION .
NOTE:
Perform the check from step 2 since there is no ON position for the trunk room light.
1. Turn the interior light switch to ON.
2. Check that the interior light operates properly.
Does the interior light illuminate?

Yes : Go to 7.

No : Go to 2.
CHECK THE LIGHTS .
1. Disconnect the connector of the light which did not illuminate.
2. Check between the connector terminals of the light (ON position).
  Connector & terminal
  
  Spot map light
  
  (Rf3) No. 1 - (Rf3) No. 13:
  
  Room light
  
  (Rf43) No. 3 - (Rf43) No. 1:
3. Check between the connector terminals of light (door position).
  Connector & terminal
  
  Spot map light
  
  (Rf3) No. 1 - (Rf3) No. 4:
  
  Room light
  
  (Rf43) No. 3 - (Rf43) No. 2:
4. Check between the connector terminals of trunk room light.
  Connector & terminal
  
  (R141) No. 1 - (R141) No. 2:
- Is the resistance less than 1 Ω? (Except for spot map light)
- Is the resistance approximately 18 Ω? (Spot map light)
Yes : Go to 3.

No : Repair or replace the light.
CHECK FUSE .
Check the F/B fuse No. 26. Ref. to LIGHTING SYSTEM>RELAY AND FUSE>INSPECTION>CHECK FUSE

Is the fuse OK?

Yes : Go to 4.

No : Replace the fuse.
CHECK CONNECTOR .
Check the connecting condition of connector.

Is the connector firmly installed?

Yes : Go to 5.

No : Repair or replace the defective part.
CHECK HARNESS .
1. Disconnect the connector of the light which did not illuminate.
2. Check the harnesses between light (ON position) connector and chassis ground.
  Connector & terminal
  
  Spot map light
  
  (Rf11) No. 13 - Chassis ground:
  
  Room light
  
  (Rf43) No. 1 - Chassis ground:
Is the resistance less than 10 Ω?

Yes : Go to 6.

No : Repair or replace the defective part.
CHECK HARNESS .
Check the harness between the F/B fuse No. 26 (downstream side) and the light.

Connector & terminal

Spot map light

F/B fuse No. 26 (downstream side) - (Rf11) No. 1:

Room light

F/B fuse No. 26 (downstream side) - (Rf43) No. 3:

Trunk room light

F/B fuse No. 26 (downstream side) - (R141) No. 1:

Is harness normal?

Yes : The interior light system is normal. (Except for trunk room light)

For trunk room light, check the operation. Go to 7.

No : Repair or replace the defective part.
CHECK OPERATION .
1. Turn the interior light switch to the DOOR position.
  NOTE:
  The trunk room light is not provided with a switch.
2. Open a door or trunk lid.
  - Check the spot map light or interior light: Open any door.
  - Check the trunk room light: Open the trunk lid.
Does the interior light illuminate?

Yes : The interior light system is normal.

No : Go to 8.
CHECK HARNESS .
Check the harnesses between light connector and body integrated unit.

Connector & terminal

Spot map light

(Rf11) No. 4 - (i81) No. 9:

Room light

(Rf43) No. 2 - (i82) No. 10:

Trunk room light

(R141) No. 2 - (i83) No. 30:

Is harness normal?

Yes : Go to 9.

No : Repair or replace the defective part.
CHECK CURRENT DATA .
Using the Subaru Select Monitor, display the following items in the [Data monitor] of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR
- [Driver's door SW input]
- [P-door SW input]
- [Rear right door SW input]
- [Rear left door SW input]
- [R Gate SW input]
Does the display switch between [OFF] ←→ [ON] when a door or trunk lid is opened/closed?

Yes : Replace the body integrated unit. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>BODY INTEGRATED UNIT

No : Check the door switch and harness.