vacuum DODGE NEON 2000 Service Workshop Manual

pull the plunger to the top of the valve (Fig. 5). In
this position there is minimal vapor flow through the
valve.
During periods of moderate intake manifold vac-
uum the plunger is only pulled part way back from
the inlet. This results in maximum vapor flow
through the valve (Fig. 6).
VEHICLE EMISSION CONTROL INFORMATION
LABEL
DESCRIPTION
All models have a Vehicle Emission Control Infor-
mation (VECI) Label. DaimlerChrysler permanently
attaches the label in the engine compartment. It can-
not be removed without defacing information and
destroying the label.
The label contains the vehicle's emission specifica-
tions and vacuum hose routings. All hoses must be
connected and routed according to the label.
REMOVAL AND INSTALLATION
EVAP CANISTER
REMOVAL
(1) Disconnect the negative battery cable.
(2) Raise vehicle and support.
(3) Disconnect the hoses from the EVAP canister
(Fig. 7).
(4) Remove 1 nuts from the bracket of the EVAP
canister (Fig. 8).
(5) Remove EVAP canister from bracket.
Fig. 4 Engine Off or Engine BackfireÐNo Vapor
Flow
Fig. 5 High Intake Manifold VacuumÐMinimal Vapor
Flow
Fig. 6 Moderate Intake Manifold VacuumÐMaximum
Vapor Flow
Fig. 7 EVAP Canister
Fig. 8 EVAP Bracket and Bracket
PLEMISSION CONTROL SYSTEMS 25 - 29
DESCRIPTION AND OPERATION (Continued)

INSTALLATION
(1) Install EVAP canister to Bracket (Fig. 8).
(2) Install 2 nuts to EVAP canister and bracket
and tighten nuts to 6.7 N´m (60 in. lbs.).
(3) Connect hoses.
(4) Install EVAP canister and bracket to vehicle
and tighten nut 22.4 N´m (250 in. lbs.).
(5) Lower vehicle.
(6) Connect negative battery cable.
LEAK DETECTION PUMP
REMOVAL
(1) Raise and support vehicle on a hoist.
(2) Push locking tab on electrical connector to
unlock and remove connector.
(3) loosen the sway bar bracket to remove the
pump bracket.
(4) Remove pump and bracket as an assembly.
(5) Disconnect lines from LDP.
(6) Remove filter.
(7) Remove pump from bracket.
INSTALLATION
(1) Install pump to bracket and tighten bolts to 1.2
N´m (10.6 in. lbs.).
(2) Install filter and tighten to 2.8 N´m (25 in.
lbs.).
(3)Before installing hoses to LDP, make sure
they are not cracked or split. If a hose leaks, it
will cause the Check Engine Lamp to illumi-
nate.Connect lines to the LDP.
NOTE: The LDP bracket must be between the rail
and sway bar bracket.
(4) Install pump and bracket assembly to body and
tighten bolts to 5.0 N´m (45 in. lbs.).
(5) Install sway bar bracket bolt and tighten bolts
to 33.8 N´m (25 ft. lbs.).
(6) Install electrical connector to pump and push
locking tab to lock.
(7) Lower vehicle(8) Use the DRB scan tool, verify proper operation
of LDP.
PROPORTIONAL PURGE SOLENOID VALVE
The solenoid attaches to a bracket near the steer-
ing gear (Fig. 9). The solenoid will not operate unless
it is installed correctly.
REMOVAL
(1) Raise vehicle and support.
(2) Disconnect electrical connector from solenoid.
(3) Disconnect vacuum tubes from solenoid.
(4) Remove solenoid from bracket.
INSTALLATION
The top of the solenoid has TOP printed on it. The
solenoid will not operate unless it is installed cor-
rectly.
(1) Install solenoid on bracket.
(2) Connect vacuum tube to solenoid.
(3) Connect electrical connector to solenoid.
(4) Lower vehicle.
Fig. 9 Proportional Purge Solenoid Valve
25 - 30 EMISSION CONTROL SYSTEMSPL
REMOVAL AND INSTALLATION (Continued)

HEATING AND AIR CONDITIONING
TABLE OF CONTENTS
page page
GENERAL INFORMATION
A/C APPLICATION TABLE...................2
HEATER AND AIR CONDITIONING CONTROL...2
HEATER AND AIR CONDITIONING............2
INTRODUCTION..........................3
SAFETY PRECAUTIONS AND WARNINGS......4
DESCRIPTION AND OPERATION
A/C REFRIGERANT LINES..................4
BLOWER MOTOR RESISTOR................5
COMPRESSOR...........................5
COMPRESSOR FRONT SHAFT SEAL..........6
CONDENSATION DRAIN TUBE...............6
ENGINE COOLING SYSTEM REQUIREMENTS...6
EVAPORATOR PROBE......................6
HANDLING TUBING AND FITTINGS...........6
HIGH PRESSURE CUT OUT SWITCH..........6
LOW PRESSURE CUT OFF SWITCH..........6
SIDE WINDOW DEMISTERS................7
SYSTEM AIRFLOW........................7
SYSTEM OIL LEVEL.......................7
VACUUM CONTROL SYSTEM................8
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST..................9
BLOWER MOTOR ELECTRICAL DIAGNOSIS....9
BLOWER MOTOR VIBRATION AND/OR
NOISE DIAGNOSIS.....................11
COMPRESSOR NOISE DIAGNOSIS..........11
EVAPORATOR PROBE TEST................11
EXPANSION VALVE.......................11
HEATER PERFORMANCE TEST.............13
LOW PRESSURE CUT OFF SWITCH.........14
SYSTEM CHARGE LEVEL TEST.............14
VACUUM CONTROL SYSTEM...............15
SERVICE PROCEDURES
CHARGING A/C SYSTEM..................17EVACUATING REFRIGERANT SYSTEM........18
R-134a REFRIGERANT....................19
SERVICING REFRIGERANT OIL LEVEL.......19
SYSTEM LEAK CHECKING.................20
REMOVAL AND INSTALLATION
A/C FILTER/DRIER.......................20
A/C SERVICE PORT VALVE CORES..........21
BLOWER MOTOR AND WHEEL ASSEMBLY....21
BLOWER MOTOR RESISTOR...............22
BLOWER MOTOR WHEEL.................22
COMPRESSOR..........................22
COMPRESSOR CLUTCH/COIL ASSEMBLY.....23
CONDENSATION DRAIN TUBE..............25
CONDENSER............................25
DISCHARGE LINE........................26
EVAPORATOR...........................26
EVAPORATOR PROBE.....................26
EXPANSION VALVE.......................27
HEATER CORE..........................28
HEATER HOSES.........................28
HIGH PRESSURE CUT OUT SWITCH.........29
HIGH PRESSURE RELIEF VALVE............29
LIQUID LINE............................29
LOW PRESSURE CUT OFF SWITCH.........29
MODE CONTROL CABLE..................30
RECIRCULATION DOOR ACTUATOR.........31
SUCTION LINE..........................31
TEMPERATURE CONTROL CABLE...........32
UNIT HOUSING..........................32
DISASSEMBLY AND ASSEMBLY
HEATER-A/C HOUSING....................34
ADJUSTMENTS
MODE CONTROL CABLE..................34
TEMPERATURE CONTROL CABLE...........34
PLHEATING AND AIR CONDITIONING 24 - 1

GENERAL INFORMATION
A/C APPLICATION TABLE
Item Description Notes
Vehicle PL Neon
System expansion valve
Total Refrigerant
CapacityR134a 765 grams / 27 oz / 1.69 lbs
Total Oil Capacity ND-8 PAG oil 180 ml / 6.10 oz
Compressor Nippondenso 10S17
Freeze-up Control Fin sensor-3 wire input to PCM, evaporator mounted, cycles
clutch off below 34É F, cycles back on
above 45É F
Low psi Control opens < 14 psi, resets > 38 psi expansion valve mounted
High psi Control opens > 470 psi, resets < 370 - 330 psi compressor mounted switch
Control head manual type
Mode Door cable
Blend Air Door cable
Fresh/Recirc door vacuum actuator
Blower Motor control head switched resistor block
Cooling Fan variable speed PCM controlled ISO solid state fan relay
Clutch
Control relay PCM
Draw 2.5 amps @ 12V60.5V @ 70É F
Gap 0.014º - 0.0269
DRB IIIT
Reads TPS, RPM, A/C switch test, fin sensor
A/C & fan relays
Actuators fan & clutch relays
HEATER AND AIR CONDITIONING CONTROL
Both the heater-only and heater-A/C systems use a
combination of, electrical, cable, and vacuum con-
trols. These controls provide the vehicle operator
with a number of setting options to help control the
climate and comfort within the vehicle. Refer to the
owner's manual in the vehicle glove box for more
information on the features, use, and suggested oper-
ation of these controls.
The heater-only or heater-A/C control panel is located
to the right of the instrument cluster on the instrument
panel. The control panel contains rotary-type knobs.
There is a blower motor speed switch, mode control
switch, temperature control, and airflow control.
The heater-only or heater-A/C control panel cannot
be repaired. If faulty or damaged, the entire unit
must be replaced. The control knobs and the illumi-
nation lamps are available for service replacement.
HEATER AND AIR CONDITIONING
All vehicles are equipped with a common heater-
A/C housing assembly (Fig. 1). The system combines
air conditioning, heating, and ventilating capabilities
in a single unit housing mounted under the instru-
ment panel. On heater-only systems, the evaporator
coil is omitted from the housing and replaced with an
air restrictor plate.
Outside air enters the vehicle through the cowl top
opening at the base of the windshield, and passes
through a plenum chamber to the heater-A/C system
blower housing. Air flow velocity can then be
adjusted with the blower motor speed selector switch
on the heater-A/C control panel. The air intake open-
ings must be kept free of snow, ice, leaves, and other
obstructions for the heater-A/C system to receive a
sufficient volume of outside air.
24 - 2 HEATING AND AIR CONDITIONINGPL

It is also important to keep the air intake openings
clear of debris because leaf particles and other debris
that is small enough to pass through the cowl ple-
num screen can accumulate within the heater-A/C
housing. The closed, warm, damp and dark environ-
ment created within the heater-A/C housing is ideal
for the growth of certain molds, mildews and other
fungi. Any accumulation of decaying plant matter
provides an additional food source for fungal spores,
which enter the housing with the fresh air. Excess
debris, as well as objectionable odors created by
decaying plant matter and growing fungi can be dis-
charged into the passenger compartment during
heater-A/C system operation.
The heater and optional air conditioner are blend-
air type systems. In a blend-air system, a blend-air
door controls the amount of unconditioned air (or
cooled air from the evaporator on models with air
conditioning) that is allowed to flow through, or
around, the heater core. A temperature control knob
on the heater-A/C control panel determines the dis-
charge air temperature by moving a cable, which
operates the blend-air door. This allows an almost
immediate manual control of the output air tempera-
ture of the system.
The mode control knob on the heater-only or heat-
er-A/C control panel is used to direct the conditioned
air to the selected system outlets. The mode control
switch uses a cable to control the mode door, while
the recirculation air door is operated by a vacuum
actuator motor.On air conditioned vehicles, the outside air intake
can be shut off by selecting the recirculation mode
(Recirc) with the mode control knob. This will oper-
ate a vacuum actuated recirculating air door that
closes off the outside fresh air intake and recirculates
the air that is already inside the vehicle.
The optional air conditioner for all models is
designed for the use of non-CFC, R-134a refrigerant.
The air conditioning system has an evaporator to cool
and dehumidify the incoming air prior to blending it
with the heated air. This air conditioning system
uses an evaporator probe to maintain minimum
evaporator temperature and prevent evaporator
freezing, and cycles the compressor clutch.
INTRODUCTION
Both the heater and the heater/air conditioning
systems share many of the same functioning compo-
nents. This group will deal with both systems
together when component function is common, and
separately when they are not.
For proper operation of the instrument panel con-
trols, refer to the Owner's Manual provided with the
vehicle.
To service the heater core or evaporator, the unit
housing must be removed from the vehicle (Fig. 2).Fig. 1 Common Blend-Air HVAC (Heating,
Ventilation, Air Conditioning) System - Typical
1 ± TEMPERATURE BLEND/AIR DOOR
2 ± EVAPORATOR CORE
3 ± BLOWER
4 ± PANEL DEFROST DOOR
5 ± HEAT DEFROST DOOR
6 ± HEATER CORE
7 ± RECIRCULATING AIR DOOR
Fig. 2 HVAC Unit Housing
1 ± AIR DISTRIBUTION
2 ± RECIRCULATION DOOR VACUUM ACTUATOR
3 ± AIR INLET
4 ± BLOWER MOTOR
5 ± EVAPORATOR PROBE CONNECTOR
6 ± CONTROL CABLES
7 ± VACUUM HARNESS
PLHEATING AND AIR CONDITIONING 24 - 3
GENERAL INFORMATION (Continued)

NOTE: The oil used in the compressor is ND8 PAG
R-134a refrigerant oil. Only refrigerant oil of the
same type should be used to service the system.
Do not use any other oil. The oil container should
be kept tightly capped until it is ready for use.
Tightly cap afterwards to prevent contamination
from dirt and moisture. Refrigerant oil will quickly
absorb any moisture it comes in contact with. Spe-
cial effort must be used to keep all R-134a system
components moisture-free. Moisture in the oil is
very difficult to remove and will cause a reliability
problem with the compressor.
It will not be necessary to check oil level in the
compressor or to add oil unless there has been an oil
loss. Oil loss at a leak point will be evident by the
presence of a wet, shiny surface around the leak.
REFRIGERANT OIL LEVEL CHECK
When an air conditioning system is first assem-
bled, all components (except the compressor) are
refrigerant oil free. After the system has been
charged with R-134a refrigerant and operated, the oil
in the compressor is dispersed through the lines and
components. The evaporator, condenser, and filter-
drier will retain a significant amount of oil, refer to
the Refrigerant Oil Capacities chart. When a compo-
nent is replaced, the specified amount of refrigerant
oil must be added. When the compressor is replaced,
the amount of oil that is retained in the rest of the
system must be drained from the replacement com-
pressor. When a line or component has ruptured and
oil has escaped, the compressor should be removed
and drained. The filter-drier must be replaced along
with the ruptured part. The oil capacity of the sys-
tem, minus the amount of oil still in the remaining
components, can be measured and poured into the
suction port of the compressor.
VACUUM CONTROL SYSTEM
The neon uses vacuum to operate only the recircu-
lation door (Fig. 9). All other controls are cable.
When vacuum is supplied to the actuator, the door
moves to the Recirculation position (Fig. 10). Theactuator is spring loaded so the door moves to the
Outside-air position when there is no vacuum sup-
plied. The operation of the door can be viewed by
removing the blower motor and looking up into the
unit inlet.
REFRIGERANT OIL CAPACITIES
Refrigerant Oil Capacities
Component ml oz
Total System 180ml 6.1 oz
Filter-Drier 30 ml 1.0 oz
Condenser 30 ml 1.0 oz
Evaporator 59 ml 2.0 oz
All Refrigerant Lines 44 ml 1.5 oz
Fig. 9 A/C Vacuum Line
1 ± BRAKE POWER BOOSTER
2 ± A/C VACUUM CHECK VALVE
3 ± VACUUM HARNESS
Fig. 10 Recirculation Air Door Vacuum Actuator
1 ± OUTSIDE AIR/RECIRC DOOR HOUSING
2 ± VACUUM ACTUATOR LINKAGE
3 ± FOAM SEAL
4 ± RECIRC DOOR VACUUM ACTUATOR
5 ± DOOR LEVER
6 ± DOOR LEVER
24 - 8 HEATING AND AIR CONDITIONINGPL
DESCRIPTION AND OPERATION (Continued)

Normally, vacuum is supplied to the actuator by
placing the Circulation control knob in the Recircula-
tion position. The Mode and the circulation control
are mechanically interlocked so the circulation con-
trol cannot be placed in the RECIRC position if the
mode control is at or between the mix and defrost
positions. Vacuum is supplied to the actuator only
when circulation control is at the RECIRC position.
If the circulation control is between the outside air
position and RECIRC position the system will be in
outside air. If the circulation control is in the
RECIRC position and the mode control is moved from
the floor to the defrost positions, the circulation con-
trol will move from the RECIRC position, to the out-
side air position beginning at the mix position. This
is to prevent window fogging.
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST
The air conditioning system is designed to remove
heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
heater A/C unit, is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins in the evaporator, moisture in the air condenses
to water, dehumidifying the air. Condensation on the
evaporator fins reduces the evaporators ability to
absorb heat. During periods of high heat and humid-
ity, an air conditioning system will be less effective.
With the instrument control set to RECIRC, only air
from the passenger compartment passes through theevaporator. As the passenger compartment air dehu-
midifies, A/C performance levels rise.
PERFORMANCE TEST PROCEDURE
Review Safety Precautions and Warnings in this
group before proceeding with this procedure. Air tem-
perature in test room and on vehicle must be 21É C
(70ÉF) minimum for this test.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer and manifold gauge set.
(2) Set control to A/C, RECIRC, and PANEL, tem-
perature lever on full cool and blower on high.
(3) Start engine and hold at 1000 rpm with A/C
clutch engaged.
(4) Engine should be warmed up with doors and
windows closed.
(5) Insert a thermometer in the left center A/C
outlet and operate the engine for five minutes. The
A/C clutch may cycle depending on ambient condi-
tions.
(6) With the A/C clutch engaged, compare the dis-
charge air temperature to the A/C Performance Tem-
peratures chart.
(7) If the discharge air temperature fails to meet
the specifications in the performance temperature
chart. Refer to the Refrigerant Service Procedures for
further diagnosis.
A/C PERFORMANCE TEMPERATURES
Ambient Temperature 21ÉC (70ÉF) 26.5ÉC (80ÉF) 32ÉC (90ÉF) 37ÉC (100ÉF) 43ÉC (110ÉF)
Air Temperature at Left
Center Panel Outlet1-8ÉC
(34-46ÉF)3-9ÉC
(37-49ÉF)4-10ÉC
(39-50ÉF)6-11ÉC
(43-52ÉF)7-18ÉC
(45-65ÉF)
Compressor Discharge
Pressure After the Filter
Drier1034-1724 kPa
(150-250 PSI)1517-2275 kPa
(220-330 PSI1999-2620
kPa (290-380
PSI)2068-2965
kPa (300-430
PSI)2275-3421 kPa
(330-496 PSI)
Evaporator Suction
Pressure103-207 kPa
(15-30 PSI)117-221 kPa
(17-32 PSI)138-241 kpa
(20-35 PSI)172-269 kpa
(25-39 PSI)207-345 kPa
(30-50 PSI)
BLOWER MOTOR ELECTRICAL DIAGNOSIS
Refer to the Blower Motor Electrical System Diag-
nosis chart (Fig. 11) in this section. Also refer to
Group 8W, Wiring Diagrams for more information.
PLHEATING AND AIR CONDITIONING 24 - 9
DESCRIPTION AND OPERATION (Continued)

WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO2 PERSONAL INJURY CAN RESULT.
(7) If suction side low pressure is within specified
range, freeze the expansion valve control head (Fig.
13) for 30 seconds. Use a super cold substance (liquid
CO2).Do not spray refrigerant on the expansion
valve for this test.Suction side low pressure should
drop to 34.5 kPa (5 psi) If not, replace expansion
valve.(8) Allow expansion valve to thaw. The low pres-
sure gauge reading should stabilize at 103 to 241
kPa (15 to 35 psi). If not, replace expansion valve.
(9) When expansion valve test is complete, test
A/C overall performance. Refer to the Heater and A/C
Performance Test in this section. Remove all test
equipment before returning vehicle to use.
HEATER PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
Review Safety Precautions and Warnings in this
group before performing the following procedures.
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap and
turn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference chart.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
Fig. 12 Evaporator Probe Harness Connector
1 ± PIN #3
2 ± PIN #2
3 ± PIN #1
Fig. 13 Expansion Valve & Low Pressure Cut-Off
Switch - Typical
1 ± EXPANSION VALVE
2 ± LOW PRESSURE CUT OFF SWITCH
3 ± SUCTION LINE
4 ± CONTROL HEAD
TEMPERATURE REFERENCE CHART
Ambient Temp. Minimum
FloorOutlet
Temp.
Celsius Fahrenheit Celsius Fahrenheit
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
PLHEATING AND AIR CONDITIONING 24 - 13
DIAGNOSIS AND TESTING (Continued)

VACUUM CONTROL SYSTEM
Use an adjustable vacuum test set (Special Tool
C-3707-B) and a suitable vacuum pump to test the
heater-A/C vacuum control system. With a finger
placed over the end of the vacuum test hose probe
(Fig. 15), adjust the bleed valve on the test set gauge
to obtain a vacuum of exactly 27 kPa (8 in. Hg.).
Release and block the end of the probe several times
to verify that the vacuum reading returns to the
exact 27 kPa (8 in. Hg.) setting. Otherwise, a false
reading will be obtained during testing.
Fig. 14 Charge Determination Chart
Fig. 15 Adjust Vacuum Test Bleed Valve - Typical
1 ± VACUUM PUMP TOOL C-4289
2 ± VACUUM TEST SET C-3707
3 ± BLEED VALVE
4 ± PROBE
PLHEATING AND AIR CONDITIONING 24 - 15
DIAGNOSIS AND TESTING (Continued)

HEATER-A/C VACUUM SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
NO FORCED AIR IN
HEAT POSITION1. Vacuum line pinched or
leaking.
2. Faulty heat defroster or
mode door.
3. Faulty selector switch.
4. Vacuum check valve.1. Locate and repair vacuum leak or pinched line.
2. Test actuators and door operation. Repair as
necassary.
3. Test selector switch and replace if necessary.
4. Test check valve and replace if necessary.
NO FORCED AIR IN
PANEL POSITION1. Vacuum line pinched or
leaking.
2. Faulty mode door.
3. Faulty selector switch.
4. Vacuum check valve.1. Locate and repair vacuum leak or pinched line.
2. Test actuator and door operation. Repair as
necessary.
3. Test selector switch and replace if necessary.
4. Test check valve and replace if necessary.
NO FORCED AIR IN
DEFROST POSITION1. Vacuum line pinched or
leaking.
2. Faulty heat, defroster, or
mode door.
3. Faulty selector switch.
4. Vacuum check valve.1. Locate and repair vacuum leak or pinched line.
2. Test actuators and door operation. Repair as
necessary.
3. Test selector switch and replace if necessary.
4. Test check valve and replace if necessary.
ONE-WAY CHECK VALVE
(1) Disconnect the heater-A/C vacuum supply
(Black) tube in the engine compartment. This tube
passes through an opening in the dash panel.
(2) Remove the one-way vacuum check valve. The
valve is located on the (Black) vacuum supply hose at
the brake power booster.
(3) Connect the test set vacuum supply hose to the
heater 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 4. If not OK, replace
the faulty valve.
(4) 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
The operation of the Circulation door can be
viewed by removing the blower motor and looking up
into the unit inlet. See Blower Motor Wheel and
Assembly removal and installation in this section for
service procedures.
(1) Connect the test set vacuum probe to the heat-
er-A/C vacuum supply (Black) hose in the engine
compartment. Position the test set gauge so that it
can be viewed from the passenger compartment.
(2) Start with the Mode control in the Panel posi-
tion and the Circulation control in the Outside-air
position.
(3) Move the Circulation control to the Recircula-
tion position (the Circulation door should move intothe Recirculation position). After a short pause move
the Mode control to the Defrost position (the Circula-
tion door should move to the Outside-air position).
The test gauge should return to the calibrated set-
ting of 27 kPa (8 in. Hg.) after each selection is
made. If the gauge cannot achieve the calibrated set-
ting, the vacuum circuit or a component has a leak.
(4) If the gauge achieves the calibrated setting but
the door does not move, there is either a pinched vac-
uum line or a failed actuator.
LOCATING VACUUM LEAKS
(1) Connect the test vacuum probe to the vehicles
(Black) supply hose. Position the vacuum test gauge
so it can be viewed from the passenger compartment.
(2) Place the Mode in the Panel position and the
Circulation control in the Recirculation position.
(3) Remove the center instrument panel bezel.
(4) Remove the center vent duct.
(5) Remove and block the Supply (Black) vacuum
line at the control. The test gauge should return to
the calibrated setting of 27 kPa (8 in. Hg). If not,
there is a leak in the Supply line.
(6) If there is no leak in the Supply line, reconnect
it to the Control and remove the Actuator Feed (Red)
line from the Control. Block the vacuum connection
on the Control from where the line was removed. The
test gauge should return to the calibrated setting of
27 kPa (8 in. Hg.). If not, there is a leak in the Con-
trol.
(7) If there is no leak in the Supply line or the
Control, reconnect the Actuator Feed (Red) line to the
control. Remove and block the Actuator Feed (Red)
line at the Actuator. The actuator vacuum port is
accessible behind and above the Glove Box. The test
24 - 16 HEATING AND AIR CONDITIONINGPL
DIAGNOSIS AND TESTING (Continued)