Dodge 2000 DURANGO Service Manual page 955

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DIAGNOSIS AND TESTING (Continued)
exact 27 kPa (8 in. Hg.) setting. Otherwise, a false
reading will be obtained during testing.
Fig. 10 Adjust Vacuum Test Bleed Valve
1 – VACUUM PUMP TOOL C-4289
2 – VACUUM TEST SET C-3707
3 – BLEED VALVE
4 – PROBE
VACUUM CHECK VALVE
(1) Remove the vacuum check valve that is to be
tested. The valves are located in the vacuum supply
tube (black) at the power brake booster on the left
side of the engine compartment, and in the heater
and air conditioner vacuum take-out of the vacuum
supply tube in the engine compartment. The vacuum
check valve must be removed in order to perform the
following tests. See Vacuum Check Valve in the
Removal and Installation section of this group for the
procedures.
(2) Connect the test set vacuum supply hose to the
heater-A/C control side of the valve. When connected
to this side of the check valve, no vacuum should
pass and the test set gauge should return to the 27
kPa (8 in. Hg.) setting. If OK, go to step Step 3. If
not OK, replace the faulty valve.
(3) Connect the test set vacuum supply hose to the
engine vacuum side of the valve. When connected to
this side of the check valve, vacuum should flow
through the valve without restriction. If not OK,
replace the faulty valve.
HEATER-A/C CONTROLS
(1) Connect the test set vacuum probe to the heat-
er-A/C vacuum supply (black) tube in the engine
compartment. Position the test set gauge so that it
can be viewed from the passenger compartment.
(2) Place the heater-A/C mode control switch knob
in each mode position, one position at a time, and
pause after each selection. The test set gauge should
HEATING AND AIR CONDITIONING
return to the 27 kPa (8 in. Hg.) setting shortly after
each selection is made. If not OK, a component or
vacuum line in the vacuum circuit of the selected
mode has a leak. See Locating Vacuum Leaks in the
Diagnosis and Testing section of this group.
CAUTION: Do not use lubricant on the switch ports
or in the holes in the plug, as lubricant will ruin the
vacuum valve in the switch. A drop of clean water
in the connector plug holes will help the connector
slide onto the switch ports.
LOCATING VACUUM LEAKS
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO
RESTRAINT SYSTEMS BEFORE ATTEMPTING ANY
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect the vacuum harness connector from
the back of the heater-A/C mode control switch on
the instrument panel.
(2) Connect the test set vacuum hose probe to each
port in the vacuum harness connector, one port at a
time, and pause after each connection (Fig. 11). The
test set gauge should return to the 27 kPa (8 in. Hg.)
setting shortly after each connection is made. If OK,
replace the faulty heater-A/C control. If not OK, go to
Step 3.
Fig. 11 Vacuum Circuit Test
24 - 25
GROUP 8M - PASSIVE
STEERING COLUMN, OR