Astra L4-1.8L (2009)
Body Control Systems: Description and Operation
Body Control System Description and Operation (Underhood Electrical Center)
Body Control System Description and Operation (Underhood Electrical Center)
Under hood Electrical Center (UEC)
The UEC is a central module in the engine compartment near to the battery. It contains a fuse and relay box as well as a control unit. The control unit
communicates with other bus users via the LS CAN bus. The UEC controls, amongst other things, the front lighting, the windscreen wipers and the horn.
Various sensors are read (e.g. brake fluid level sensor) and their values are output by the UEC as bus messages.
Wiper Function
The UEC is the centre of all actuated components:
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Front wiper relay
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4 wiper stages (one-touch wipe, intermittent, slow wipe, fast wipe). If the drivers door is opened when the fast stage is selected, the wiper is
automatically reset to the slow stage. This function is programmable.
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Rain/light sensor.
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Intermittent function (with rain sensor fitted).
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Wiper service position: After the ignition has been switched off and the key is in position "0", the wipers can be moved to a service position (for
example to change the wipers) by actuating the wiper switch in the SCCM.
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Rear wiper.
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Windscreen wash system.
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Rear window wash system (If the washer fluid level is too low, the rear window wash system will be deactivated).
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Headlamp wash system (If the washer fluid level is too low, the headlamp wash system will be deactivated).
Exterior Lighting Function
The following functions are actuated depending on the corresponding signal input:
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Turn signal function.
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Parking light left/right.
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Position light.
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Dipped beam.
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Daytime running lamps (programmable according to country).
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Automatic light function (if fitted with rain/light sensor).
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Lights-on warning (if position or dipped beam lights are on and the drivers door is opened with the key removed from the ignition, a warning
buzzer will sound).
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Emergency lighting (if, when the ignition is on, the UEC does not receive any bus messages or the bus messages are illegible, the dipped beam and
position light are activated).
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"Follow me home" functions (if the headlamp flash stalk is operated with the key removed from the ignition, the lights switched off and the driver's
door open, the UEC will switch on the dipped beam, the reversing lights and the tail lights for 30 seconds).
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Main beam: The UEC will only switch on main beam if the dipped beam is switched on. (On vehicles with rain/light sensors, the main beam can
only be switched on if the sensor has reported that it is "night", the dipped beam is switched on and the engine is running).
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There are two programmable options for main beam operation: A: The UEC switches off dipped beam when main beam is operated. B: Both main
beam and dipped beam are on together.
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Headlamp flash (warning: if the key is removed and the door open, the same stalk will switch on the "follow me home" function).
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Front fog lamps (can only be activated if the ignition is switched on and the position light or main beam are switched on).
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Bulb check.
