Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Exterior Lighting / Description and Operation

Land Rover Discovery (2009–2016) Service Manual / Electrical / Lighting / Headlamps / Exterior Lighting / Description and Operation


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Exterior Lighting Description and Operation

  1. Stop lamp switch
  2. Rain/Light sensor
  3. Side turn signal indicator lamp
  4. Headlamp
  5. Front fog lamp
  6. Battery Junction Box (BJB)
  7. Reverse lamp switch

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  1. High Mounted Stop Lamp (HMSL)
  2. License plate lamp
  3. Front height sensor (Xenon headlamps only)
  4. Rear height sensor (Xenon headlamps only)
  5. Left steering column multifunction switch
  6. Instrument Cluster (IC)
  7. Auxiliary lighting switch
  8. Hazard warning lamp switch
  9. Central Junction Box (CJB)
  10. Headlamp Levelling Control Module (HLCM)
  11. Rear fog lamp
  12. Tail lamp unit


Exterior lighting

The exterior lighting consists of:

  1. Two headlight assemblies, each containing a:
  • Headlamp
  • Static bending lamp
  • Turn signal indicator lamp
  • Combined daytime running lamp and side lamp
  • Side marker lamp and reflector (NAS only).
  1. Two tail lamp assemblies, each containing a:
  • Turn signal indicator lamp
  • Tail lamp unit
  • Stop lamp
  • Rear side markers
  • Reverse lamps
  1. lighting control switch and steering column multifunction switch.
  2. Central Junction Box (CJB).
  3. Two front fog lamps
  4. Two rear fog lamps.
  5. A High Mounted Stop Lamp (HMSL).
  6. Two license plate lamps.
  7. Two side repeater lamps.
  8. A Headlamp Levelling Control Module (HLCM).
  9. Two front and rear height sensors (Xenon headlamps only).
  10. An auto high beam camera (model/market dependant).
  11. Auxiliary lighting switch.
  12. A Stop lamp switch.
  13. Reverse lamp switch.
  14. Stop lamp switch.
  15. A rear fog lamp switch.
  16. A hazard warning lamp switch.
  17. Warning indicators.
  18. Rain/Light sensor.
  19. Battery Junction Box..

The exterior lighting is controlled by the CJB as follows:

  • Control and monitoring of the exterior lamps including the turn signal indicators and hazard warning lamp functionality.
  • Monitoring and evaluation of control inputs from other system control modules and output of applicable messages in the instrument cluster message centre.

The CJB is connected to the Medium Speed (MS) and High Speed (HS) Controller Area Network (CAN) buses. The CJB contains a microprocessor which performs the control, monitoring and evaluation of functions.

The headlamp Levelling control module provides signals to control headlamp Levelling and, where fitted, the Adaptive Front lighting System (AFS) headlamps.

Driver lighting selections are made using the lighting control switch and left steering column multifunction switch, the rear fog lamp switch and the hazard warning lamp switch. The CJB operates the brake lamps using the inputs from the Stop lamp switch.

Depending on model and market specification, the lighting system may have:

  • An auto high beam function, where the headlamps are automatically switched between low and high beam in response to signals from the auto high beam camera.
  • An autolamps function, where the exterior lights are automatically turned on or off in response to signals from the rain/light sensor used for automatic wiper operation.

    For additional information, refer to: Wipers and Washers (501-16 Wipers and Washers, Description and Operation).

All headlamps have their signalling functions controlled by LED (light emitting diode)'s within the headlamp assemblies.

Driver lighting selections using the left steering column multifunction switch are passed to the CJB via the clockspring on a Local Interconnect Network (LIN) bus. The auxiliary lighting switch is hardwired directly to the CJB and is only used for manual headlamp Levelling on vehicles with halogen headlamps. The CJB provides circuit protection for all exterior lighting circuits.

The lighting system has an 'auto' lights function which is controlled by the CJB on receipt of signals from the rain/light sensor located at the top of the windshield. The exterior lights are turned on or off in response to ambient light signals from the rain/light sensor on a LIN bus connection to the CJB .

The auto lights can also be activated when the windshield wipers are activated by signals from the rain sensor, or when the driver activates the wipers in the continuous wipe position for more than 20 seconds.

Three levels of headlamp specification are available:

  • halogen,
  • xenon,
  • xenon with Adaptive Front lighting System (AFS).

In certain markets the headlamps feature a static bending lamp which illuminates the area at the side of the vehicle when turning into driveways for example. Only the D3S xenon bulb and the xenon ballast resistor are serviceable, no other headlamp components are available individually.

Failure of any Light Emitting Diode (LED) requires replacement of the complete lamp assembly.

The tail lamps comprise a single lamp assembly on each side of the vehicle.

The turn signal indicator, tail and stop lamps, side marker lamps and reverse lamps are located in each tail lamp assembly. Rear fog lamps are mounted in the rear bumper. The rear lamp assemblies require removal for bulb replacement.

All versions of the headlamps have impact resistant polycarbonate lenses.

Removable covers at the rear of the headlamps allow for bulb replacement.

The headlamps require removal for bulb replacement.

The headlamps use a projector unit. The xenon headlamps use a D3S xenon bulb which operates in both low and high beam. Halogen projector headlamps use a HB3 halogen bulb which also operates in both low and high .

Headlamp washer jets are a standard fitment on xenon headlamps.

Headlamp washer jets are a standard fitment on xenon headlamps.

Static dynamic Levelling is standard on all xenon headlamps. The static dynamic system uses height sensors fitted to the front and rear suspension and a Headlamp Levelling Control Module (HLCM) which process the height sensor signals and adjust the headlamp vertical alignment accordingly.

Manual headlamp Levelling is used only on vehicles fitted with halogen projector lamps. A rotary Levelling thumbwheel is located in the auxiliary lighting switch in the instrument panel, adjacent to the steering column.

Turn signal indicators and high and low beam functions are controlled from the left steering column multifunction switch. The turn signal indicators have a lane change feature. A single press and release of the multifunction switch in either direction will operate the selected turn signal indicators for 3 cycles.

An Image Processing Control Module (IPCM) system may also be fitted as an optional feature which automatically controls the high beam headlamps.


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