Pontiac FIREBIRD 1972 Service Manual page 29

1972 PONTIAC SERVICE MANUAL
Fig. 1-9 Ventilation Air Flow
-
Typical
While outside air is distributed from either the heater
system or the purge opening in the heater case at all times
and is available from the lower vents and/or the upper
center vents on the instrument panel, if desired, the air
flow in the passenger compartment follows the same pat-
tern. Inside air leaves the passenger compartment by pass-
ing under the rear seat into the trunk, then forward along
the body sides to the lock pillars where the air escapes to
the outside by means of pressure relief valves (Fig. 1-9).
body sides to the lock pillars where the air escapes to the
outside by means of pressure relief valves (Fig. 1-9).
HEATER CONTROL FUNCTIONAL TEST
-
EXCEPT X SERIES
Functional tests are to be made with engine running and
coolant warm.
1. Move system selector lever to OFF, set fan switch to
HI position and move temperature lever to full
WARM (HOT).
A. B Series
-
Blower operates with all air coming out
purge opening at RH end of heater case.
B. Except B Series
-
Blower operates but little or no
air flows from the heater or defroster outlets.
2. Move system selector lever to NORMAL
(HEATER). Make sure lever is engaged in detent.
A. Hot air comes chiefly from heater outlet with
some air from defroster nozzles.
3. Move system selector lever to DEFROST
A. Hot air comes chiefly from defroster nozzles with
some air from heater outlet.
4. Move temperature lever to OFF (COLD).
A. Air from defroster is about the same temperature
as the air outside the car.
5. Move fan switch to OFF (LO on B Series), pausing
at each detent.
A, G AND F
SERIES
All G and F Series and A Series models without side vent
pane windows are equipped with an upper ventilation sys-
tem in addition to the lower vents previously described.
Air outlets which may be individually controlled are built
in at each end of the instrument panel. These outlets per-
mit quiet circulation of air without the corresponding
wind and road noise present with an open window.
Air through the upper vent system is controlled by a knob
at each individual kick pad just above the knob which
controls the lower vent.
Inside air leaves the passenger compartment by passing
under the rear seat into the trunk, then forward along the
A. B Series
-
Blower speed and air flow decrease at
each detent until low speed is obtained.
B. Except B Series
-
Blower speed and air flow de-
crease and stop at full OFF position.
6. B Series Only
-
Move selector lever of OFF.
A. Blower continues to run at low speed but all air
comes from purge opening on heater case.
Should heater operate satisfactorily during above checks,
it would appear that heater operation is normal. If during
checks, irregularities or complaints are noted, refer to
Trouble Diagnosis for cause and correction.