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AIR CONDITIONING
24-27
Fig. 33-Healer
Thermostatic Valve Test
the two temperature thermostats. Tie these together
through a tee, and connect them to the vacuum
test
set, Tool C-3707. Disconnect the vacuum hose at the
water valve and seal the vacuum hose end (Fig.
31).
Push and release the plunger on the temperature
selector switch a few times while watching the vacu-
um gauge (Fig. 32). A drop of more than one-half inch
in vacuum indicates excessive leakage, either in the
vacuum lines and connections, or in the switch itself.
A vacuum hose leak may be located by running your
fingers along the suspected area while watching the
vacuum gauge. If the hose is otherwise in good con-
dition, the faulty spot can be cut out and the hose
spliced, using a short length of
3/1s
inch-diameter thin-
walled copper tubing.
If inspection of the vacuum hoses doesn't uncover
the leak, replace the temperature selector switch. Be-
fore you install the replacement switch, it's a good
idea to connect the vacuum hoses to
it
and repeat
the test.
A I C &
Heater Temperufure Selector
Switch Adjustment
(1)
The switch is operated by the heat door when
the "cool7' button is depressed. The turnbuckle should
be adjusted so that the rubber edge of the heater
door seals along its full length with minimum defor-
mation. The heater door will be open
%
inch in the
defrost position.
(2) After step
1
depress the heater button. Adjust
the vacuum switch by placing a
.060
inch spacer be-
tween the switch plunger and the depression lever.
Move the switch until the plunger is fully depressed,
and tighten the switch in this position and remove the
spacer (Refer to Fig.
12).
AIR CONDITIONING AND HEATER
TEMPERATURE CONTROL CABLE ADJUSTMENT
To adjust the temperature control cable do so at
the lever end of the cable. Make
sure
the cable hous-
ing extends ?h inch beyond the retainer clip at the
stat assembly. If the cable is badly out of adjustment
at the thermostatic valve end,
it
may not be possible
to get the proper adjustment at the lever end. To ad-
just the control cable:
1.
Remove the retainer clip and cable at the con-
trol lever end.
2. Pull out on the control cable wire to move the
thermostat valves to the full
off or
closed position.
3. Hold the temperature control lever in the
"Off"
position, install control cable wire eyelet on the
lever arm.
4.
Install the retainer clip to hold the adjustment.
THERMOSTATIC VALVE TESTS
A complaint of erratic heat output, or no heat at
all, could be traced to a faulty thermostatic valve. Be-
fore you perform the following tests, always inspect
first for pinched or leaking vacuum hoses and test
the temperature selector switch to be
sure it
isn't
leaking. Also make sure the vacuum line fitting at the
top of the water flow valve isn't leaking.
Test preparations. Turn the ignition switch to the
"Accessory" position, turn the blower switch to the
number two position and push the "Cool" button.
The blower should be kept running for the entire
test. Place a thermometer in the upper grille outlet
so you'll know when the temperature is stabilized.
Don't begin the test until the air temperature remains
constant within one degree per minute. While you're
waiting for the temperature to level out, remove the
radio speaker grille and the speaker to make
it
easier
to get at the thermostatic valves. Then remove the
small-diameter vacuum hoses from the right-hand
side of the two thermostats.
Also, disconnect the vacuum source hose for the
air-conditioning unit from the intake manifold. Con-
nect the hose to vacuum pump, Tool C-3652 and start
the pump. A vacuum of at least twenty inches is re-
quired for this test.
In addition, you'll need the Tool C-3707 vacuum
gauge test set with a special test hose attached. The
dimensions of this test hose are very important; it
must be exactly forty-eight inches long and have
an
inside diameter of three-sixteenths inch. The specifi-
cations for this test have been calibrated for this
specific hose, so don't try to substitute another size!
HEATER THERMOSTATIC VALVE TEST
(Fig.
331
To test the heater thermostatic valve-left-hand-
thermostat-connect the test hose from the vacuum
gauge test set to the outlet side of the heater ther-
mostat. The heater thermostat and
its inlet
and outlet
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