Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Headlamps

PRINCIPLES OF OPERATION

For a detailed description of the Headlamps, refer to the relevant Description and Operation section in the workshop manual. REFER to: Exterior Lighting (417-01 Exterior Lighting, Description and Operation).

SAFETY INFORMATION

WARNING:

The xenon headlamp system generates up to 28,000 volts. Make sure that the headlamps are switched off before working on the system.

Failure to follow this instruction may result in personal injury.

The following safety precautions must be followed when working on the xenon headlamp system:

  1. DO NOT attempt any procedures on the xenon headlamps when the lights are switched on.
  2. Handling of the xenon bulb must be performed using suitable protective equipment, e.g. gloves and goggles. The glass part of the bulb must not be touched.
  3. Xenon bulbs must be disposed of as hazardous waste.
  4. Only operate the lamp in a mounted condition in the reflector.

There are comprehensive instructions on the correct procedures for xenon headlamp system repairs in the manual, refer to section 100-00 - General Information, Standard Workshop Procedures of the workshop manual.

REFER to: Standard Workshop Practices (100-00 General Information, Description and Operation).

INSPECTION AND VERIFICATION

CAUTION:

Diagnosis by substitution from a donor vehicle is NOT acceptable.

Substitution of control modules does not guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor vehicle.

NOTES:

  • If a control module or a component is suspect and the vehicle remains under manufacturer warranty, refer to the Warranty Policy and Procedures manual, or determine if any prior approval programme is in operation, prior to the installation of a new module/component.
  • When performing voltage or resistance tests, always use a digital multimeter that has the resolution ability to view 3 decimal places.

    For example, on the 2 volts range can measure 1mV or 2 K Ohm range can measure 1 Ohm. When testing resistance always take the resistance of the digital multimeter leads into account.

  • Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
  1. Verify the customer concern
  2. Visually inspect for obvious signs of damage and system integrity

Visual Inspection

Visual Inspection

  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
  2. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index
  3. Check DDW for open campaigns. Refer to the corresponding bulletins and SSMs which may be valid for the specific customer complaint and carry out the recommendations as required

SYMPTOM CHART

SYMPTOM CHART

SYMPTOM CHART

SYMPTOM:

Headlamp(s) inoperative

POSSIBLE CAUSE:

  • Body system fault
  • Headlamp bulb failed
  • Lighting control switch fault
  • Headlamp circuit short circuit to ground, short circuit to power, open circuit, high resistance

ACTION:

  • Using the Jaguar Land Rover approved diagnostic equipment, check the central junction box for related DTCs and refer to the relevant DTC index
  • Install a new headlamp bulb
  • Install a new lighting control switch
  • Refer to the electrical circuit diagrams and check the headlamp circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness or install a new headlamp bulb as necessary

SYMPTOM:

Headlamp(s) dim

POSSIBLE CAUSE:

  • Body system fault
  • Headlamp bulb failed
  • Headlamp bulb incorrect specification
  • Headlamp circuit high resistance
  • Low voltage

ACTION:

  • Using the Jaguar Land Rover approved diagnostic equipment, check the central junction box for related DTCs and refer to the relevant DTC index
  • Install a new headlamp bulb
  • Install a new headlamp bulb
  • Refer to the electrical circuit diagrams and check the headlamp circuit for high resistance.

    Repair the wiring harness or install a new headlamp bulb as necessary

SYMPTOM:

Headlamp(s) stuck on

POSSIBLE CAUSE:

  • Body system fault
  • Lighting control switch fault
  • Headlamp circuit short circuit to power

ACTION:

  • Using the Jaguar Land Rover approved diagnostic equipment, check the central junction box for related DTCs and refer to the relevant DTC index
  • Install a new lighting control switch
  • Refer to the electrical circuit diagrams and check the headlamp circuit for short circuit to power. Repair the wiring harness as necessary

SYMPTOM:

Headlamp low/high beam switching function inoperative

POSSIBLE CAUSE:

  • Body system fault
  • Lighting control switch fault
  • Headlamp shutter circuit short circuit to ground, short circuit to power, open circuit, high resistance
  • Headlamp internal failure - Shutter mechanism

ACTION:

  • Using the Jaguar Land Rover approved diagnostic equipment, check the central junction box for related DTCs and refer to the relevant DTC index
  • Install a new lighting control switch
  • Refer to the electrical circuit diagrams and check the headlamp shutter circuit for short circuit to ground, short circuit to power, open circuit, high resistance. Repair the wiring harness or install a new headlamp as necessary
  • Install a new headlamp

SYMPTOM:

Warning indicator(s) inoperative

POSSIBLE CAUSE:

  • Body system fault
  • Instrument cluster fault
  • Lighting control switch fault

ACTION:

  • Using the Jaguar Land Rover approved diagnostic equipment, check the central junction box for related DTCs and refer to the relevant DTC index
  • Using the Jaguar Land Rover approved diagnostic equipment, check the instrument cluster for related DTCs and refer to the relevant DTC index
  • Install a new lighting control switch

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