Alfa Romeo 166 Booklet page 114

GAS DISCHARGE HEADLIGHTS
(optional for versions/markets where
applicable)
Gas discharge headlights (xenon) work
with a voltaic arc, in an atmosphere satu-
rated with pressurised xenon gas, instead
of the incandescent filament.
The lighting produced is remarkably
higher than that of the conventional light
in both terms of the quality of the light
(lighter) and of the amplitude and posi-
tion of the lit area.
The advantages offered by better light-
ing are noted (due to less sight fatigue
and better orientation capability of the
driver, thus of travelling safety) especially
in bad weather, fog and/or insufficient
signs, because of the higher lighting
of the side beams which are normally
shaded.
The heavy increase of lighting in the
side beams considerably increases driving
safety because it allows the driver to bet-
ter see other users at the sides of the
road (pedestrians, cyclists and motorcy-
clists).
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Very high voltage is needed to trigger
the voltaic arc, after which the supply can
be at low voltage.
The headlights reach their maximum in-
tensity after about 15 seconds from
switching on.
The high luminosity produced by this
type of headlight calls for the use of an
automatic system to keep the headlight
beam aiming constant and prevent daz-
zling other vehicles when braking, accel-
erating and carrying loads.
The electromechanical system for auto-
matic constant beam aiming makes the
headlight aiming device superfluous.
Xenon lights are very long-lasting and
failure is unlikely.
WARNING
If necessary, have the
system checked and any
repairs done only by Authorized Al-
fa Romeo Services.