Cadillac 1967 VVI Data Book page 157

A slight downward pressure on top of the switch provides
high beam, regardless of the amount of outside light. This
arrangement permits signaling an approaching driver if he
fails to switch to low beam, and also provides a simple check
for the automatic position of the foot switch.
A sensitivity control ring located directly behind the head-
light control knob permits adjusting the sensitivity of the
Power Headlight Control. This ring is identified by the words
"AUTO DIMMING" above the ring. Centering the control
ring pointer between "OFF" and "FAR" provides normal
sensitivity. Rotating the control ring clockwise toward the
word "FAR" causes the lights to dim sooner; rotating it
counterclockwise delays the dimming action.
For conventional operation of headlight dimming, rotate the
sensitivity control ring counterclockwise to the "OFF"
position.
TWILIGHT
SENTINEL
29
Cadillac Twilight Sentinel (optional at extra cost) automatically
turns on the car's driving lights as darkness approaches, when
the ignition switch is "ON". The unit also turns the lights off
as daylight approaches. The unit is designed so that the car's
headlights will not turn on when driving short distances under
viaducts, trees, etc., or turn off when passing under bright
lights.
The Twilight Sentinel control lever is located behind the
headlight control knob (on cars equipped with Guide-Matic
Power Headlight Control, the control lever is located behind
the sensitivity control ring).
For automatic operation, move the control lever counter-
clockwise away from the "OFF" position. Leave the headlight
control knob all the way in. The car's lights will automatically
turn "ON" as darkness approaches and "OFF" as daylight
approaches. If the driver desires to turn the car's headlights
on during daylight hours, which may be necessary to identify
the car in such conditions as fog, rain or when driving through
a tunnel, he may do so by pulling out the headlight control
knob.
An adjustable time delay feature permits the lights to remain
"ON" after the ignition switch is turned "OFF" to provide a
path of light for driver and passengers as they leave the car.
Additional side lighting can be obtained by activating a
cornering light with the turn signal lever. For TIME DELAY