Adjustment Actuator - Alfa Romeo 159 Training Material

ELECTRICAL
SYSTEM
The automatic corrector also improves driving comfort because the illuminated area is stabilised and the driver's eye
does not need to constantly adapt to changes of lighting.
The device consists of:
a stepper actuator for each headlight
two load sensors connected to the front and rear suspensions on the right-hand side.
Correction function
Correction is made by means of the load sensor signal which, connected to the suspensions, provides an indication
of vehicle load.
The ECU is activated at key-on and resets the headlights to the exact position calculated according to vehicle load
after moving them to end of stroke position and back.
The load sensor signals are regularly acquired and appropriate mediated to readjust the position of the headlight if
necessary (e.g. fuel consumption while travelling). This readjustment is not immediate. It is filtered in time to avoid
undesired corrections (e.g. potholes, rough roads, etc.).
This correction is also performed when the lights are off so that the beam is correctly positioned the instant the
headlights come on.
Load sensors
The load sensors are fastened to the vehicle chassis. An appropriately shaped lever follows the movement of the
suspension. The sensor is powered by the headlight ECU and provides a linear output signal which is proportional to
the position of the suspension with respect to the body.
A. Connector
B. Control lever
a. Lever camber
V. Sensor output signal voltage

9.8.5 Adjustment actuator

A stepper actuator inside the light cluster makes the adjustment. It consists of a electrical stepper motor and a worm
screw reducer which transforms the rotary movement into linear motion of a pin hinged via a ball joint to the reflecting
surface.
1. Stepper motor
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