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AIR CONDITIONING
24-25
Fig. 2 6 A d j u s t Vacuum Test Bleed Valve
uum, with a finger blocking the prod on the end of
the test hose (Fig. 26).
It is absolutely essential that the bleed valve be ad-
justed
so
the vacuum gauge pointer will return to ex-
actly 8 inches when the prod is covered by a finger.
Otherwise a false reading will be obtained when the
control circuit is tested.
CAUTION: Alternately release and reblock the
hose prod several times. Make sure the bleed valve
is adjusted so the vacuum gauge pointer returns to
exactly 8 inches of vacuum when the prod is cov-
ered with
a
finger.
Disconnect the engine vacuum source hose at the
"T" connector under the instrument panel, and in-
sert the vacuum tester hose prod into the source hose
leading to the control switch.
Start the test by pushing the "Heat" button. The
i "
Fig. 27-Connector
Plug Installed Uypicall
vacuum tester gauge needle will drop until the actua-
tor has operated, and then will return to 8 inches.
Continue to push button "Defrost," "Cool," and
"Off'
allowing time for actuators to operate after each but-
ton is pushed, and note the vacuum drop below
8
inches after each operation. The maximum allowable
vacuum drop below 8 inches after each operation is
%
inch.
If the vacuum drop is more than
%
inch,
first
re-
check the tester for reading exactly 8 inches. If cor-
rect, inspect the
fit
of the 7-hole connector plug on
the control switch (Fig. 27). This plug must be posi-
tioned all the way on the 7 prods on the control
switch.
CAUTION: Do not use lubricant on the switch
prods or in the holes in the plug, as lubricants will
ruin the vacuum valve in the switch.
If
it is impos-
sible to properly position the connector plug all
the way on the switch prods, put a drop or two of
clean water in the holes of the connector plug.
This
will allow the plug to slide completely on switch
prods.
Retest:
If vacuum drop is now within limits, pro-
ceed with TEST
1,
"Test System Pressure." If vacu-
um drop is still in excess of
3 h
inch, remove connec-
tor plug from switch. Insert the vacuum test prod
alternately in each of the connector holes except the
source hose connector hole (Fig. 28). Note the amount
of vacuum drop below 8 inches after each actuator
has operated. If the vacuum test gauge comes back to
8 inches at each of the 6 holes, the hoses and actua-
tors are not leaking. The control switch is faulty and
62x681
Fig. 28-Vacuum
Tube Assembly Test
1. Spot cool door actuator
open
2. To maximum cool vacuum switch
3. Spot cool door actuotor closed
4. To maximum cool vacuum switch
5. Defroster door actuator open
6. Vacuum
source
7. Defroster door actuator cloied
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