Pontiac FIREBIRD 1972 Service Manual page 1301

CHASSIS ELECTRICAL 12-31
n
-FUSIBLE LINK
T O GENERATOR
Fig. 12-34 Typical Fusible Link
the extreme counterclockwise position the instrument
panel lights are completely off and the dome light is
turned on. Second, the beam switch (foot operated) deter-
mines if the headlamp country (bright) beam or traffic
(dim) beam is on when the main lighting switch is pulled
out. A red indicator lamp (blue on B and F Series) on the
instrument panel glows when the headlamp country beam
is on.
Parking lamps use a two filament bulb. One filament is for
the directional signal and the other is for the parking
lamp.
Side marker lamps adjacent to the front parking lamp and
in the rear quarter panel are single filament (rear) or
double filament (front) lamps. The rear lamps show red
and the front amber.
Headlamps are of sealed beam construction so that light
source, reflector, lens, and lens gasket are all assembled in
one sealed unit. When the filament burns out or lens is
cracked or broken, the entire unit is readily replaceable
with a new unit.
The filaments used in the twelve volt headlamps are very
fragile, therefore, the headlamp units must be handled
carefully.
The headlamps must be properly aimed in order to obtain
maximum road illumination and safety that has been built
into the headlamp lighting equipment. The headlamps
must be checked for proper aim whenever a sealed beam
unit is replaced and after any adjustment or repairs of
front end sheet metal assembly.
Regardless of method used for checking headlamp aim,
car must be at normal weight, that is, with gas, oil, water
and spare tire. Tires must be uniformly inflated to speci-
fied pressure (see Section 10). If car regularly carries an
unusually heavy load in rear compartment or trailer, these
loads should be on car when headlamps are checked. Some
states have special requirements for headlamp aiming ad-
justment and these requirements should be known and
observed.
Horizontal aiming of each sealed beam is provided by
adjusting screws which move mounting ring in body
against tension of springs. There is no adjustment for
focus since sealed beam unit is set for proper focus when
it is manufactured.
Headlamp aiming equipment is commercially available.
Follow manufacturers recommendations for use of this
equipment.
Lighting for ash tray illumination on A, G and F Series
comes from the instrument panel cluster. The light is
transmitted by a system called "fiber optics" lighting. This
lighting system consists of flexible plastic feeders, corn-
posed of thin plastic fibers enclosed in black plastic tubing,
which transmit the light.
The tail lamp lens on B (except station wagons), G and
F
Series contain small circles of reflex (about 1/8" diameter)
covering its entire surface. Thus, when lights are directed
at the rear of the car, the entire tail lamp appears to light
up. The A and X Series lens continues to have a small
section of reflex in the tail lamp lens rather than the entire
surface. This is a safety advantage for a driver following
a a car which has a tail lamp burned out. The B Series
station wagons have two separate reflectors mounted in
the rear bumper.
The tail lamp bulb is a double filament bulb which acts as
stop, tail and turn signal lamp. The bulb can be removed
by removing the tail lamp lens on A, G and station wagon
series or removing bulb and socket from inside trunk on
B, F and X Series.
STOP LAMP SWITCH
The stop lamp switch must be checked whenever brake
pedal height has been changed. Adjustment is made by
positioning the switch and bracket in relation to pedal
arm.
NOTE: Make sure that switch does not restrict
pedal action.
The two horns installed on most cars (Fig. 12-35) are
designed to give a blended tone when operated together.
Each horn utilizes a solenoid-actuated diaphragm to deve-
lop a resonating air column in horn projector.
A relay is inserted in the horn circuit because of high
current required to operate horns. The relay reduces
length of heavy gauge wire required and provides a more
direct connection between horns and battery. Conse-
quently, higher voltage is available at the horns and better
performance is obtained by eliminating voltage drop
which otherwise would be in the horn button wiring cir-
cuit.