Exterior Lighting

Exterior Lighting

The BC1 controls all Exterior Lighting functions of the MINI except the reverse lights. There are no back-up, substitute lighting or warning indications in the event of a bulb failure.

Purpose of the System
The BC1 provides control over exterior lighting and illumination of instrumentation indicators for turn signals and high beams. The exterior lighting functions of the BC1 also provide "Follow-Me-Home" Lighting and emergency operation of limited lighting functions in the case of BC1 failure. These light functions are controlled by the BC1:

- Headlights
- Tail Lights
- Brake Lights
- Turn Signals
- Side Marker Lights
- Auxiliary Lights
- Fog Lights
- Directional Indicators
- High Beam Indicator
- License Plate Lights
- Hazard Warning Lights
- Flash to Pass Lights

The BC1 does not control, but signals for activation the optional Xenon Lights.

System Components
The Exterior Lighting System contains the following primary components:

- Master Light Switch
- Headlamp Assemblies
- Tail Lamp Assemblies
- Front Turn Signal Assemblies
- Fog Lights and Fog Light Relay (Optional)
- Xenon Light Assemblies (Optional, Includes DHL)


Main Light Switch


The Main Light Switch is located to the left of the steering column. Functions of the switch are:


- Low Beam Headlamps
- High Beam Headlamps (and Flash to Pass)
- Turn Signals (Left and Right)
- Turn Signal Indicators
- Parking Lights
- Trip Computer Functions

Headlamp Assemblies
The Headlamp Assemblies contain the Low Beam and High Beam bulbs. Both bulbs are 12v 55w H7 type bulbs. The bulbs are replaceable from the rear of the headlamp assemblies.


Xenon Lights (Optional)
The automotive industry/press often identify xenon lighting systems as HID (high intensity discharge) systems. Xenon headlight technology was first introduced to the US market exclusively on the E32 750iL in 1993. BMW xenon headlight systems have evolved and their availability as optional equipment has spread throughout the model lineup. Blue/White in color and using ellipsoidal technology Xenon headlights provide improved night time visibility in all driving conditions compared with traditional Halogen bulb head-lights.

Xenon headlights provide the following benefits:

- Longer bulb life. Typically, xenon bulbs will last from 3 to 5 times longer than halogen.
- More light output. Xenon headlights produce from 2.5 to 3 times more lumens than halogen.
- Blue/White light (simulates natural daylight). Xenon bulbs produce a blue/white light while halogen bulbs produce a yellow light. The light color of a light source is measured in color temperature (not to be confused with thermal temperature). Color temperature is measured in Kelvin (K). The higher the color temperature the whiter the light.

Natural daylight = 4,500 to 5,000 K
Xenon headlights = 4,000 to 4,500 K
Halogen headlights = 3,200 K (yellow in color)

- Better driving visibility. The combination of higher lumens and higher color temperature provide a superior lighting source. The beam is wider and brighter in front of the vehicle than conventional halogen bulbs improving safety and driver comfort.
- Lower operating temperature.
- Lower power consumption.


Headlamps


Xenon bulbs are identified as D-2S (D= Discharge). Xenon bulbs illuminate when an arc of electrical current is established between two electrodes in the bulb. The xenon gas sealed in the bulb reacts to the electrical excitation and heat generated by the current flow. The distinct bluish/white brilliant light is the result of the xenon gas reacting to the controlled current flow.

Phases of Bulb Operation
Starting Phase: The bulb requires an initial high voltage starting pulse of 18-25RV to establish the arc.

Warm Up Phase: Once the arc is established the power supply to the bulb is regulated to 2.6Agenerating a lamp output of 75 watts. This is the period of operation where the xenon gas begins to brightly illuminate. The warm up phase stabilizes the environment in the bulb ensuring continual current flow across the electrodes.

Continuous Phase: Once the warm up phase is completed, the system switches to a continuous mode of operation. The supply voltage for the bulb is reduced and the operating power required for continual bulb illumination is reduced to 35 watts which is less than a conventional halogen bulb.

Functional Description
To regulate the power supply to the bulbs, additional components are required. The xenon control modules (1 per light) receive operating power from the BC1 when the headlights are switched on. The xenon control modules provide the regulated power supply to illuminate the bulbs through their phases of operation. The igniters establish the electric arcs. Integral coils generate the initial high voltage starting pulses from the control module provided starting voltage. Thereafter they provide a closed circuit for the regulated power output from the control modules.





Xenon Headlight Testing
Warning: Xenon headlight control systems generate high output voltage. Prior to headlight removal or testing observe the vehicle warning labels and be cautious by following safeguards to prevent accidental injury.

Use test adapter 90 88 6 631 010 for testing of Xenon Lights. The DISplus Measurement System includes all the cable connection information as well as Test Modules.

Dynamic Headlight Adjustment (DHL - Xenon Only)
Cars equipped with Xenon headlights require automatic headlight aim control; this necessitates a separate control module to carry out automatic adjustment of the headlights. With automatic headlight leveling, the load status and its changes are recorded by means of two height level sensors (potentiometers) located at the front and rear axles. The information from these sensors is communicated back to the DHL module.

Each headlight has electrically driven linear stepper motors, which are connected to the headlamp inserts in such a way that their movement changes the range of the headlamp.





DHL Headlight Adjustment Control Module is located under the dash on the drivers side.


Principle of Operation
Headlights

Low beams are switched on when the main light switch is set to position 2 with the ignition switch in position 2. Pulling the low beam/high beam switch towards the driver with the ignition in position 1 or 2 activates the headlight flasher (flash to pass). Flash to pass is active with the low beams OFF or ON.

High beam lights are activated by pulling the low beam/high beam switch toward the driver until its end position is reached. Pulling the switch a second time de-activates the high beams. The low beam lights must be on and the ignition switch in position 2 for high beam activation.

Operation of the optional Xenon headlights is the same.


Tail Lights
The Tail Lights and license plate lights are ON any time the main light switch is in position 1 or 2. It is not necessary for the ignition to be on.


Brake Lights
The Brake Lights are triggered by the hall-effect brake light switch signal to the BC1. The ignition must be ON for the brake lights to be active. Failure of the brake light switch will cause the brake lights to be ON anytime the ignition is on. The third brake light is an LED type and is serviced as a complete unit only.


Turn Signals
Movement of the turn signal stalk up or down will activate the Left/Right turn signals with the ignition on. Placement of the stalk switch up or down with the ignition off will activate parking lights only on the side requested.

Flashing of the turn signals is controlled by the BC1.

The left hand and right hand direction indicator lamps in the instrument cluster will always be synchronized with the respective vehicle direction indicators. The Body Control Module (BC1) controls operation of the indicator LED in the cluster via the K-bus.

Hazard Warning Lights
The hazard warning function is activated via the hazard warning switch integrated into the instrument cluster, the direction indicator lamps will be turned on (flash cycle). The lamps are turned off when the hazard switch is reselected regardless of the ignition switch position and the direction indicator switches.


Fog Lights
Front fog lights can only be switched on when the side lights or low beam headlights are switched on. The front fog lamps are powered via an external relay located in the engine compartment fuse box. The Body Control Module (BC1) controls the front fog light relay. The front fog light indicator in the fog light switch is driven from the output of the relay.


Follow-Me-Home Lights
To activate the follow-me-home function, with the low beam on, turn the ignition to position 0 or 1 from position 2 and switch the master light switch to the off position. The low beams will remain on for 30 seconds, then turn off.


Crash Activation
The direction indicator lights will be turned on (flash cycle), when the vehicle inertia switch is triggered. The direction indicators will continue to flash until the hazard warning switch is operated which will turn off the direction indicator lights.

Reverse Lights
Control of the Reverse Lights is handled by the reverse light switch in the manual transmission or the ECVT. B+ is supplied through the switch when reverse gear is engaged.

Emergency Light Operating Mode
An emergency backup hardware circuit completely independent of the BC1 will ensure certain lights can function in the event of a failure within the BC1.

During normal operation a cycling frequency from the BC1 deactivates this emergency circuit. This cycling frequency should be at least 15 Hz. Emergency operation is initiated if this does not take place.

The emergency mode provides the following lights from ignition position 1 regardless of the light switch position:
- Front sidelights
- Rear sidelights
- Low beam lamps
- Left and right brake lamps (when the brake switch is active)

The following functions will not operate in Emergency Mode:

- Direction indicator lamps
- Hazard warning lamps
- Main beam lamps
- Front fog lamps
- Communication via the K-bus
- Instrument/switch illumination