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Interior Lighting System: Overview Ford Focus I facelift

Interior/illumination Lights 2 illustrations ~1699 words

The interior lighting system consists of the following components

  1. Generic electronic module (GEM)
  2. Central junction box (CJB)
  3. Interior/map lamps
  4. Cargo lamp
  5. Door ajar switches
  6. Liftgate/liftgate glass ajar switches
  7. Ambient lighting module (if equipped)
  8. Ambient lighting switch (if equipped)

The interior lighting system may consist of up to 3 subsystems

  1. Courtesy lamps
  2. Demand lamps
  3. Ambient lighting (if equipped)

The courtesy lamps are controlled by the GEM. The courtesy lamp subsystem consists of the interior dome lamps. The turns on the courtesy lamps when a door is opened or an UNLOCK signal is received from the remote keyless entry (RKE) transmitter.

The demand lamps system consists of the front dome lamp, map lamps, and the luggage compartment lamp (3-door, 5-door or sedan) or the cargo lamp (wagon). The GEM controls the demand lamps by providing ground for the battery saver relay.

The ambient lighting system consists of the ambient lighting switch, the ambient lighting module, and the harness with hard-wired light emitting diodes (LEDs) all located within the floor console. The ambient lighting is turned on by the headlamp switch. Whenever the parking lamps are on, power is supplied to the ambient lighting module. The ambient lighting switch is used to cycle the LEDs through 7 different color combinations or to turn the ambient lighting off. The ambient lighting module provides the necessary voltage to the LEDs to illuminate the cup holders (front and rear) and the front and rear footwell areas.

Special Tools Illustration Tool Name Tool Number Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool 73III Automotive Meter 105-R0057 or equivalent Flex Probe Kit 105-R025C or equivalent

Scheme 1

Scheme 1: Interior Lighting
Scheme 1: Interior Lighting

Scheme 2

Scheme 2
Scheme 2

Principles of Operation

The front interior lamp is off, regardless of the state of the interior lighting feature, when the interior lamp switch is in the OFF position.

The front interior lamp is on, regardless of the state of the interior lighting feature, when the interior lamp switch is in the ON position.

The system illuminates the interior lamp to improve visibility of the vehicle interior while a door is open.

The front interior lamp follows the status of the illuminated entry feature, when the interior lamp switch is in the illuminated entry position.

The front interior lamp illuminates when any of the following occurs

  1. Any of the vehicle's doors are open (not including the tailgate or luggage compartment).
  2. The ignition switch is in the OFF or ACC position and an UNLOCK command is activated.
  3. The ignition switch is turned from RUN or START to ACC or OFF.

The front interior lamp turns off when all of the vehicle's doors are closed (not including the tailgate or luggage compartment) and any of the following occurs

  1. 25 seconds has elapsed since either the lights were turned on or the last door was closed while the vehicle is not locked (whichever occurs first).
  2. The ignition switch is turned from OFF or ACC to RUN or START.
  3. The ignition switch is in the OFF or ACC position and a LOCK command is activated.

In addition, the interior lamp turns off when the battery saver relay timer has expired.

When the interior lamps are being turned off due to the battery saver feature, the lamps are turned off immediately, with no delay (ramp down).

Normal Operation

The generic electronic module (GEM) grounds the control side of the battery saver relay located in the central junction box (CJB). When the relay is energized, voltage is supplied to the interior lamps through circuit 29-LC7 (OG/BU). The GEM monitors the door ajar switch status on circuits 31S-GL9 (BK/YE) (LH front), 31S-GL12 (BK/OG) (LH rear), 31S-GL16 (BK/BU) (RH front) and 31S-GL19 (BK/GN) (RH rear). The door ajar switches are normally open when the doors are closed. When the GEM determines a door is open, the GEM then controls the ground side of the interior lamp on circuit 31S-LC7 (BK/BU) to illuminate the interior lamp.

Possible Causes

  1. Fuse
  2. Circuit 29-LC7 (OG/BU) open
  3. Circuit 29-LC7A (OG/BU) open
  4. Circuit 29-LC7B (OG/BU) open (wagon)
  5. Circuit 31S-LC7 (BK/BU) open
  6. Interior lamp
  7. CJB
  8. GEM

The generic electronic module (GEM) grounds the control side of the battery saver relay located in the central junction box (CJB). When the relay is energized, voltage is supplied to the cargo lamp through circuits 29-LC7 (OG/BU) and 29-LB6 (OG/YE). The ajar switch controls the ground side of the cargo lamp on circuits 31S-LB6 (BK/YE) and 31S-LB1 (BK/BU) to illuminate the cargo lamp.

Possible Causes

  1. Circuit 29-LB6 (OG/YE) open
  2. Circuit 31S-LB6 (BK/YE) open
  3. Circuit 31S-LB1 (BK/BU) open
  4. Circuit 31-GL20 (BK) open
  5. Liftgate latch
  6. Cargo lamp

The generic electronic module (GEM) monitors the door ajar switch status on circuits 31S-GL9 (BK/YE) (LH front), 31S-GL12 (BK/OG) (LH rear), 31S-GL16 (BK/BU) (RH front) and 31S-GL19 (BK/GN) (RH rear). The door ajar switches are normally open when the doors are closed. When the GEM determines a door is open, the GEM then controls the ground side of the interior lamp on circuit 31S-LC7 (BK/BU) to illuminate the interior lamp.

Possible Causes

  1. Circuit 31S-GL9 (BK/YE) short to ground
  2. Circuit 31S-GL12 (BK/OG) short to ground
  3. Circuit 31S-GL16 (BK/BU) short to ground
  4. Circuit 31S-GL19 (BK/GN) short to ground
  5. Front lamp
  6. Door ajar switch
  7. GEM

The generic electronic module (GEM) monitors the door ajar switch status on circuits 31S-GL9 (BK/YE) (LH front), 31S-GL12 (BK/OG) (LH rear), 31S-GL16 (BK/BU) (RH front) and 31S-GL19 (BK/GN) (RH rear). The door ajar switches are normally open when the doors are closed. When the GEM determines a door is open, the GEM then controls the ground side of the interior lamp on circuit 31S-LC7 (BK/BU) to illuminate the interior lamp.

Possible Causes

  1. Circuit 31S-GL9 (BK/YE) open
  2. Circuit 31S-GL12 (BK/OG) open
  3. Circuit 31S-GL16 (BK/BU) open
  4. Circuit 31S-GL19 (BK/GN) open
  5. Circuit 31-GL9 (BK) open
  6. Circuit 31-GL12 (BK) open
  7. Circuit 31-GL16 (BK) open
  8. Circuit 31-GL19 (BK) open
  9. Door ajar switch
  10. GEM

The illuminated entry feature is activated by the generic electronic module (GEM). The GEM receives a signal transmitted by the remote keyless entry (RKE) transmitter. The GEM then grounds the control side of the battery saver relay. When the relay is energized, voltage is supplied to the interior lamps through circuit 29-LC7 (OG/BU).

Possible Causes

  1. RKE system

The generic electronic module (GEM) provides a ground circuit for the battery saver relay. The battery saver relay provides power to circuit 29-LC7 (OG/BU). Circuit 29-LC7 (OG/BU) provides power to each demand lamp switch. When the demand lamp switch is activated, power is provided to the selected demand lamp. The demand lamps are grounded through circuit 31-LC7 (BK).

Possible Causes

  1. Circuit 31-LC7 (BK) open
  2. Circuit 31-LC7A (BK) open (wagon)
  3. Interior lamp

The generic electronic module (GEM) provides a ground circuit for the battery saver relay located in the central junction box (CJB) through circuit 31S-LC22 (BK/OG). The battery saver relay provides power to circuit 29-LC7 (OG/BU). Circuit 29-LC7 (OG/BU) provides power to each demand lamp switch. When the demand lamp switch is activated, power is provided to the selected demand lamp.

Possible Causes

  1. Circuit 29-LC7 (OG/BU) short to voltage
  2. Circuit 31S-LC22 (BK/OG) short to ground
  3. CJB
  4. GEM

The generic electronic module (GEM) monitors the trunk ajar status on circuit 31S-GL20 (BK/RD). The trunk ajar switch is a dual throw style switch. One side of the switch is normally closed when the luggage compartment is closed, and the other side is open when the luggage compartment is closed. When the GEM determines the luggage compartment is open, the GEM then energizes the battery saver relay. When the relay is energized, voltage is supplied to the luggage compartment lamp through circuits 29-LC7 (OG/BU) and 29-LB25 (OG/BU). The ajar switch controls the ground side of the luggage compartment lamp on circuit 31-AA27 (BK) to illuminate the luggage compartment lamp.

Possible Causes

  1. Circuit 29-LB25 (OG/BU) open
  2. Circuit 31S-LB25 (BK/BU) open
  3. Circuit 31S-LB1 (BK/BU) open
  4. Circuit 31S-GL20 (BK/RD) short to ground
  5. Circuit 31-GL20 (BK) open
  6. Circuit 31-AA27 (BK) open
  7. Luggage compartment lid/liftgate latch
  8. Luggage compartment lamp
  9. GEM

When the ambient lighting module receives voltage from the headlamp switch (with the parking lamps on), the ambient lighting module supplies voltage and ground to the light emitting diodes (LEDs) located in the floor console. The ambient lighting switch is used to cycle through the 7 color combinations or to turn the ambient lighting feature off. There are 3 different color (red, blue and green) LEDs housed within each LED assembly.

When the headlamp switch is in the PARKING LAMPS ON or HEADLAMPS ON position, the ambient lighting switch and the ambient lighting module receives voltage through an in-line fuse (3A) on circuit 29S-LC23 (OG/WH) (shared with the parking lamps voltage supply circuit). Ground for the ambient lighting module is provided through circuit 31-LC23 (BK). When the ambient lighting switch is pressed, voltage is routed to the ambient lighting module through circuit 10-LH53 (GY/OG), indicating a request for the module to cycle the ambient lighting to the next setting.

Possible Causes

  1. In-line fuse
  2. Circuit 10-LH53 (GY/OG) open or short to voltage
  3. Circuit 29S-LC23 (OG/WH) open
  4. Circuit 31-LC23 (BK) open
  5. Ambient lighting harness
  6. Ambient lighting switch
  7. Ambient lighting module

When the ambient lighting module receives voltage from the headlamp switch (with the parking lamps on), the ambient lighting module supplies voltage and ground to the light emitting diodes (LEDs) located in the floor console. The ambient lighting switch is used to cycle through the 7 different color combinations or to turn the ambient lighting feature off. There are 3 different colored (red, blue and green) LEDs housed within each LED assembly.

When the headlamp switch is in the PARKING LAMPS ON or HEADLAMPS ON position, the ambient lighting switch and the ambient lighting module receives voltage through an in-line fuse (3A) on circuit 29S-LC23 (OG/WH) (shared with the parking lamps voltage supply circuit). Ground for the ambient lighting module is provided through circuit 31-LC23 (BK). When the ambient lighting switch is pressed, voltage is routed to the ambient lighting module through circuit 10-LH53 (GY/OG), indicating a request for the module to cycle the ambient lighting to the next setting.

Possible Causes

  1. Circuit 10-LH53 (GY/OG) open or short to voltage
  2. Circuit 29S-LC23 (OG/WH) open
  3. Ambient lighting switch
  4. Ambient lighting harness
  5. Ambient lighting module

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