|
|
|
Lotus Service Notes
Section MR MR.11 - HEADLAMP ASSEMBLIES Xenon Headlamp Assemblies The Lotus Evora is available with High Intensity Discharge (HID)/Xenon headlamp assemblies, the light sources of which utilise a plasma discharge arc between two electrodes to provide a blue-white light for optimal illumination of the roadway. Each headlamp unit uses a D1S electronic igniter/burner unit (equivalent to the bulb), mounted in a specially coated alloy reflector, ahead of which is fixed a glass aspheric lens on an alloy carrier. A shielded high tension harness connects the burner unit to a voltage ballast unit mounted in the base of the headlamp housing. The ballast unit is supplied with battery voltage and outputs around 20,000 volts (up to 80,000 during the start up phase) to the burner, although the power consumption is only 35 Watts. A bottom pivoted flap is used to mask the upper part of the light beam (i.e. lower part in front of the lamp, prior to beam inversion by the aspheric lens), and allow a single light source to provide both main and dip beams. The flap is sprung and counterweighted in order to default to the vertical, masking, position, and is swung down by a solenoid fixed to the side of the reflector unit, when main beam is selected. Also contained within each headlamp housing is a 10 LED sidelamp, positioned outboard of the headlamp, and an 8 amber LED turn lamp at the front of the housing, fronted by a clear diffuser. Due to the increased light production of the gas discharge headlamps, and the increased potential for dirt on the lamp cover causing dazzle from refraction, a powerful headlamp washer is fitted. A dedicated high pres- sure pump is fitted into the windscreen washer bottle, and supplies a powerwash module incorporated into the outer side of each headlamp unit, normally lying flush with the headlamp cover. When the windscreen washer control is operated, the headlamp washer pump is also activated for 2 seconds, the pressure from which causes the telescopic washer module to extend about 20 mm above the headlamp cover and deploy two conical sprays of fluid from a pair of high flow jets. The module then returns under spring action to its flush position. Note that certain atmospheric conditions may result in some condensation inside the lamp unit. This should have no significant effect on lamp performance and is no cause for concern. Headlamp Servicing The only serviceable parts of the Xenon headlamp unit are: - D1S burner unit - Voltage ballast unit - Powerwash module - High tension cable WARNING: The high voltages produced by the headlamp ballast unit could cause injurious electric shocks. Ensure the battery is disconnected before servicing the headlamp assembly. To replace the burner unit, first disconnect the battery to protect from potentially injurious shocks. Remove the access grommet in the wheelarch liner, and pull off the protective boot from the back of the headlamp hous- ing. Release the spring wire clip and withdraw the burner sufficiently to allow the H.T. cable to be unplugged. Note that touching the glass envelope by hand is likely to lead to premature failure. If necessary, the envelope should be cleaned using white spirit and a paper tissue. Other serviceable parts may be replaced after removing the headlamp housing from the car. Halogen Bulb Headlamp Assemblies The Evora is also available with halogen bulb headlamp assemblies, which share the same housing and features of the Xenon units, but are replace the HID headlamp equipment with a simpler H4 halogen bulb. Headlamp Housing Removal Each headlamp is secured to the front subframe longeron via front and rear mounting brackets. To remove a headlamp housing: 1. Remove the front roadwheel and wheelarch liner; 2. Disconnect the wiring harness and washer tubing; 3. Release the two screws securing the headlamp front mounting bracket to the subframe, and the two fixings securing the headlamp rear bracket to the bumper support bracket. Withdraw the headlamp assembly. |