Pontiac FIREBIRD 1972 Service Manual page 747

6D-4 1972 PONTIAC SERVICE MANUAL
b. With the air cleaner in position, secure a dial type
temperature gage next to the sensor. Install air
filter cover. Do not install wing nut.
c. Start engine. When the control valve begins to
open (viewed through end of snorkel), remove air
filter cover and observe temperature gage. It must
read between 85°F. and 128°F.
CAUTION: Do not accidentally touch moving
parts such as the engine fan. When the snorkel
tube is so positioned so as to make inspection
dificult, the use of a mirror is recommended.
d. If the system fails to operate the valve at the
temperature indicated, proceed to the Motor
Check.
3. Motor Check
-
b. To determine if the motor is operable, apply at
least nine inches of vacuum (either from the en-
gine or from an independent source) to the
vacuum fitting on the motor.
c. The control valve should close the cold air pas-
sage as long as vacuum is applied. The hot air pipe
will be open.
d. If the vacuum motor fails to operate the control
valve with the direct application of vacuum, first
check to determine if the motor linkage is prop-
erly connected to the door or if a bind is present.
If the linkage is found satisfactory, then motor
replacement is indicated.'
a. With the engine shut off, the position of the con-
trol valve should be open to outside air (Fig.
e. If the motor check is found to be satisfactory,
6D-5).
then sensor replacement is indicated.
PERIODIC SERVICE
MOTOR
REMOVE
1. Drill out two spot welds initially with a 1/16" drill,
then enlarge as required to remove the retaining
strap. Do not damage snorkel tube. (Fig. 6D-7).
2. Raise motor strap retainer
3. Lift motor, cocking it to one side to unhook linkage
at the control damper.
RETAINING STRAP INSTALL REPLACEMENT
SENSOR ASSM IN SAME
POSITION A S ORIGINAL ASSM
Fig. 6D-7 Auto-Therm Motor and Sensor
INSTALL
1. Assemble in reverse order adhering to the following
notes.
a. Drill a 7/64" hole in snorkel tube at point A as
shown in Fig. 6D-8.
b. Use motor strap retainer and sheet metal screw
provided in the motor service package to secure
the retainer and motor to snorkel tube.
c. If screw interferes with operation of the damper,
shorten screw.
1
I
TEMPERATURE TRANSM~SION SOLENOID
SWITCH SWITCH VALVE
Fig. 6D-8 Components of Controlled Combustion Systems