hvac DODGE RAM 2003 Service Repair Manual

C200 - GRAY (I/P TO HVAC)
CAV CIRCUIT
1 C7 10BK/TN
2 C34 20DB/WT
3 C4 16TN
4 C32 20GY/DB
5 C6 14LB
6 C5 16LG
7 C1 10DG
8 C33 20DB/RD
9 C12 20LG/BK
10 C57 20DB/GY
11 C62 20DB/PK
12 C46 20YL/LG
13 C35 20DG/YL
C200 - (HVAC TO I/P)
CAV CIRCUIT
1 C7 10BK/TN
2 C34 20DB/WT
3 C4 16TN
4 C32 20GY/DB
5 C6 14LB
6 C5 16LG
7 C1 10DG
8 C33 20DB/RD
9 C12 20LG/BK (A/C ONLY)
10 C57 20DB/GY (A/C ONLY)
11 C62 20DB/PK
12 C46 20YL/LG (DUAL-ZONE)
13 C35 20DG/YL
C201 - (I/P TO HEADLINER)
CAV CIRCUIT
1 D25 20VT
2 Z104 20BK/OR
3 L50 18WT/TN
4 Z56 18BK
5-
6 Y107 20VT/RD
7-
8 M3 20PK/DB
9 M20 20BR
10 M11 20PK/LB
11 L1 20VT/BK
12 F32 20RD/YL
8W - 80 - 22 8W-80 CONNECTOR PIN-OUTSDR

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Door Ajar Switch-Driver (Base) BK Left Front Door 42
Door Ajar Switch-Left Rear (Base) BK Left Rear Door 43
Door Ajar Switch-Passenger (Base) BK Right Front Door N/S
Door Ajar Switch-Right Rear (Base) BK Right Rear Door 43
Door Lock Motor/Ajar Switch-Driver
(Except Base)BK Left Front Door 42
Door Lock Motor/Ajar Switch-Left
Rear (Except Base)BK Left Rear Door 43
Door Lock Motor/Ajar Switch-
Passenger (Except Base)BK Right Front Door N/S
Door Lock Motor/Ajar Switch-Right
Rear (Except Base)BK Right Rear Door 43
Door Lock Switch-Passenger BL In Right Front Door N/S
Driver Airbag Squib BK In Steering Column N/S
Driver Blend Door Actuator (Dual
Zone)BK Right Side of HVAC N/S
Driver Door Module C1 BL In Left Front Door 42
Driver Door Module C2 BL In Left Front Door 42
Engine Control Module C1 BK Left Engine 10
Engine Control Module C2 BK Left Engine 10
Engine Coolant Temperature
SensorBK Near Generator 4, 7, 9
Engine Oil Pressure Sensor BK Lower Left Side of Engine 4, 6, 8, 9, 11
Evap/Purge Solenoid BK Left Fender Side Shield 26, 28
Evaporator Temperature Sensor BK Right Side of HVAC N/S
Fog Lamp-Left WT Left Front Facia N/S
Fog Lamp-Right WT Right Front Facia N/S
Fuel Control Actuator (Diesel) BK Left Rear Engine 23
Fuel Heater (Diesel) BK Left Side Engine 10
Fuel Injector No.1 BK At Fuel Injector 4, 8
Fuel Injector No. 2 BK At Fuel Injector 3, 7
Fuel Injector No. 3 BK At Fuel Injector 4, 8
Fuel Injector No. 4 BK At Fuel Injector 3, 7
Fuel Injector No. 5 BK At Fuel Injector 4, 8
Fuel Injector No. 6 BK At Fuel Injector 3, 7
Fuel Injector No. 7 BK At Fuel Injector 4, 8
Fuel Injector No. 8 BK At Fuel Injector 3, 7
Fuel Pump Module LT GY At Fuel Tank 48
Fuel Pump Motor (Diesel) BK Left Side Engine 10
Generator BK Front of Engine 4, 6, 7, 10
Glove Box Lamp and Switch BK At Glove Box 37, 40
Governor Pressure Sensor BK Left Rear of Transmission N/S
Headlamp Switch BK Left Side of Instrument Panel 34, 37, 39
Headlamp-Left BL At Headlamp 26, 30, 31
8W - 91 - 4 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONDR
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Manifold Absolute Pressure Sensor
(5.9L)BK Left Front of Intake Manifold 8
Mode Door Actuator 1 BK Right Side of HVAC N/S
Mode Door Actuator 2 BK Right Side of HVAC N/S
Multi-Function Switch BK On Steering Column N/S
Natural Vacuum Leak Detection
AssemblyBK Rear of Transmission 18, 19
Output Speed Sensor DB Left Side of Transmission 11, 12, 14, 15
Overdrive Switch WT Center of Instrument Panel 37
Overhead Map/Reading Lamp
(Except Base)NAT Center of Headliner N/S
Oxygen Sensor 1/1 Upstream BK Left Front of Side of Transmission 11, 12, 14, 16
Oxygen Sensor 1/2 Downstream NAT Left Rear of Side of Transmission 11, 14, 16
Oxygen Sensor 2/1 Upstream BK Right Front Side of Transmission 11, 12, 14, 16, 17, 18,
19
Oxygen Sensor 2/2 Downstream BK Right Rear Side of Transmission 11, 12, 14, 16, 17, 18,
19
Park Brake Switch At Park Brake 26, 27
Park/Turn Signal Lamp-Left Front BK At Lamp 26, 30, 31
Park/Turn Signal Lamp-Right Front BK At Lamp 1, 25, 29
Passenger Airbag On/Off Switch Right Side of Instrument Panel 35, 37, 40
Passenger Blend Door Actuator
(Dual Zone)BK Right Side of HVAC N/S
Passenger Lumbar Switch At Passenger Seat N/S
Power Mirror-Left BK At Mirror 42
Power Mirror-Right BK At Mirror N/S
Power Outlet RD Center of Instrument Panel 37
Power Outlet-Console BK Center of Instrument Panel N/S
Power Seat Motor-Driver Front
VerticalRD At Driver Seat N/S
Power Seat Motor-Driver Horizontal BK At Driver Seat N/S
Power Seat Motor-Driver Rear
VerticalBK At Driver Seat N/S
Power Seat Switch-Driver BK At Driver Seat N/S
Power Seat Switch-Passenger BK At Passenger Seat N/S
Power Steering Pressure Switch BK Near Power Steering Pump 4, 5
Power Window Circuit Breaker Under Instrument Panel 33, 37, 39
Power Window Motor-Driver BK In Driver Door at Motor 42
Power Window Motor-Left Rear BK In Door at Motor 43
Power Window Motor-Passenger BK In Passenger Door at Motor N/S
Power Window Motor-Right Rear BK In Door at Motor 43
Power Window Switch-Left Rear BL In Door 43
Power Window Switch-Right Rear BL In Door 43
Powertrain Control Module C1 BK Right Rear Engine Compartment 21, 22, 23, 24
8W - 91 - 6 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONDR
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Powertrain Control Module C2 WT Right Rear Engine Compartment 21, 22, 23, 24
Powertrain Control Module C3 GY Right Rear Engine Compartment 21, 22, 23, 24
Powertrain Control Module C4 GN Right Rear Engine Compartment 21
PTO Sense Near G107 21, 22, 24
Radio (Base) GY Rear of Radio 37, 38
Radio (Premium) BK Rear of Radio 37, 38
Recirculation Door Actuator BK Right Side of HVAC N/S
Red Brake Warning Indicator
SwitchBK Near Master Cylinder 26, 28, 31
Remote Radio Switch-Left BK At Steering Wheel N/S
Remote Radio Switch-Right BK At Steering Wheel N/S
Seat Belt Pretensioner-Left YL Left B-Pillar 44, 45
Seat Belt Pretensioner-Right YL Right B-Pillar N/S
Seat Belt Switch-Driver DK GY Left B-Pillar N/S
Seat Belt Tension Reducer
(Standard Cab)YL Left B-Pillar 44
Seat Heater Interface Module GN Under Driver Seat N/S
Sentry Key Immobilizer Module BK On Steering Column 32
Side Marker - Left Front (Dual
Wheels)BK Front of Left Rear Fender 50
Side Marker - Left Rear (Dual
Wheels)BK Rear of Left Rear Fender 50
Side Marker - Right Front (Dual
Wheels)BK Front of Right Rear Fender 50
Side Marker - Right Rear (Dual
Wheels)BK Rear of Right Rear Fender 50
Speaker-Center Instrument Panel WT Center of Instrument Panel 37, 38
Speaker-Left Front Door WT In Left Front Door 42
Speaker-Left Instrument Panel BK Left Side of Instrument Panel 37, 39
Speaker-Left Rear (Standard Cab) WT In Lower Left B-Pillar 44
Speaker-Left Rear Door (Quad
Cab)WT In Left Rear Door 43
Speaker-Right Front Door WT In Right Front Door N/S
Speaker-Right Instrument Panel BK Right Side of Instrument Panel 37, 40
Speaker-Right Rear (Standard
Cab)BK In Lower Right B-Pillar N/S
Speaker-Right Rear Door (Quad
Cab)BK In Right Rear Door 43
Speed Control Servo BK Left Front Side of Engine
Compartment26, 28
Speed Control Switch - Left
(Except ETC)GN Steering Wheel N/S
Speed Control Switch - Right
(Except ETC)GN Steering Wheel N/S
Speed Control Switch-Left (ETC) WT At Steering Wheel N/S
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 7
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

SPLICE
NUMBERLOCATION FIG.
S183 Top of Transmission 12
S184 Top of Transmission 12
S191 Near Integrated Power Module 29
S197 Left Rear Engine Compartment 23
S201 Left Side of Instrument Panel 37
S204 Left Side of Instrument Panel 37
S205 Left Side of Instrument Panel 39
S206 At Steering Column N/S
S207 At Steering Column N/S
S208 Center of Instrument Panel 37, 38
S209 Center of Instrument Panel 37
S210 Center of Instrument Panel 39
S212 Left Side of Instrument Panel 33, 39
S213 Center of Instrument Panel in T/O for Instrument Cluster
ConnectorsN/S
S214 Left Side of Instrument Panel 33, 39
S216 Center of Instrument Panel 37
S217 Left Side of Instrument Panel 37, 40
S218 Left Side of Instrument Panel 39
S219 Center of Instrument Panel N/S
S220 Center of Instrument Panel N/S
S221 Center of Instrument Panel 37, 38
S222 Center of Instrument Panel 37
S224 Right Side of HVAC N/S
S225 Center of Instrument Panel 37
S226 Right Side of HVAC N/S
S230 Right Instrument Panel 37
S231 Left Instrument Panel 39
S301 Center of Headliner N/S
S302 Center of Headliner N/S
S304 Center of Headliner N/S
S305 Center of Body 44, 45
S306 Left Side of Frame N/S
S307 Center of Headliner N/S
S308 Left Rear Chassis 48, 49
S309 Center Rear of Chassis 49
S310 Center of Body 44, 45
S311 Left Front of Body 41, 44, 45
S312 Right Door N/S
S313 Left Front Door 42
S314 Left Rear Frame Rail N/S
S315 Left Front Body 41, 44, 45
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 11
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

(16) Disconnect the air bag control module electri-
cal connector.
(17) Remove the right cowl trim cover. (Refer to 23
- BODY/INTERIOR/COWL TRIM - REMOVAL)
(18) Disconnect the two electrical connectors. (Fig.
11 )
(19) Disconnect the radio antenna. (Fig. 12)
(20) Remove the one HVAC screw. (Fig. 13)(21) Using a trim stick C-4755 or equivalent, from
the notch on the bottom, remove the right end cap.
(Fig. 14)
(22) Remove the right a-pillar trim. (Refer to 23 -
BODY/INTERIOR/A-PILLAR TRIM/GRAB HANDLE
- REMOVAL)
(23) Remove the two right side mounting bolts on
the a-pillar and one right mounting bolt on the cowl
side panel. (Fig. 14)
Fig. 10 CENTER MOUNTING BOLTS
1 - INSTRUMENT PANEL
2 - BOLTS
Fig. 11 RIGHT WIRE HARNESS CONNECTIONS
1 - COWL SIDE PANEL
2 - ELECTRICAL CONNECTORS
Fig. 12 ANTENNA CONNECTION
1 - ANTENNA CABLE
2 - RADIO CABLE
Fig. 13 HVAC/INSTRUMENT PANEL MOUNTING
1-HVAC
2 - MOUNTING SCREW
3 - LOWER SURROUND SCREWS
4 - GLOVE BOX OPENING
DRINSTRUMENT PANEL 23 - 55
INSTRUMENT PANEL ASSEMBLY (Continued)

(11) Install the right a-pillar trim panel. (Refer to
23 - BODY/INTERIOR/A-PILLAR TRIM - INSTAL-
LATION)
(12) Position the right end cap and seat the
attachment clips fully.
(13) Install the one HVAC mounting screw.
(14) Connect the radio antenna.
(15) Connect the two electrical connectors at the
right cowl panel.
(16) Install the right cowl trim cover. (Refer to 23 -
BODY/INTERIOR/COWL TRIM - INSTALLATION)
(17) Connect the air bag control module electrical
connector.
(18) Install the center bracket bolts and tighten to
12 N´m (9 ft. lbs.).
(19) Install the floor console, if equipped. (Refer to
23 - BODY/INTERIOR/FLOOR CONSOLE - INSTAL-
LATION)
(20) Install the air bag control module cover, if
equipped.
(21) Connect the park brake release handle actua-
tor rod.
(22) Install the hood release handle and tighten
the screws.
(23) Install the two bolts at the column support
bracket and tighten to 14 N´m (10 ft. lbs.).
(24) Install the steering column. (Refer to 19 -
STEERING/COLUMN - INSTALLATION)
(25) Connect the wire harness electrical connectors
above the brake pedal.
(26) Install the two top instrument panel bolts and
tighten to 12 N´m (9 ft. lbs.).
(27) Install the four top instrument panel screws.
(28) Install the instrument panel top cover. (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION)
INSTRUMENT PANEL
HEADLAMP SWITCH BEZEL
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULDRESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Using a trim stick C-4755 or equivalent,
release the top clips on the steering column opening
cover and the lower drivers side bezel.
(2) Using a trim stick C-4755 or equivalent,
release the switch bezel. (Fig. 17)
(3) Disconnect the electrical connector and remove
the bezel.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, OR INSTRU-
MENT PANEL COMPONENT DIAGNOSIS OR SER-
VICE. DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE, THEN WAIT TWO
MINUTES FOR THE AIRBAG SYSTEM CAPACITOR
TO DISCHARGE BEFORE PERFORMING FURTHER
DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE
WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Connect the electrical connector.
(2) Position the switch bezel and seat the attach-
ment clips fully.
(3) Seat the clips on the steering column opening
cover and the lower drivers side bezel fully.
Fig. 17 HEADLIGHT SWITCH BEZEL
1 - SWITCH BEZEL
2 - INSTRUMENT PANEL
3 - ELECTRICAL CONNECTOR
4 - HEADLIGHT SWITCH
DRINSTRUMENT PANEL 23 - 57
INSTRUMENT PANEL ASSEMBLY (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT........................1
OPERATION
OPERATION - HEATER AND AIR
CONDITIONER........................1
OPERATION - REFRIGERANT SYSTEM
SERVICE PORT........................2DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................5
STANDARD PROCEDURE - DIODE
REPLACEMENT.......................7
SPECIFICATIONS
A/C APPLICATION TABLE................7
SPECIFICATIONS......................8
CONTROLS.............................9
DISTRIBUTION..........................24
PLUMBING.............................31
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER
All vehicles are equipped with a common HVAC
housing assembly (Fig. 1). The system combines air
conditioning, heating, and ventilating capabilities in
a single unit housing mounted under the instrument
panel.
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the HVAC
system, the engine cooling system must be properly
maintained. The use of a bug screen is not recom-
mended. Any obstructions in front of the radiator or
condenser will reduce the performance of the air con-
ditioning and engine cooling systems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Engine Cooling for
more information before the opening of, or attempt-
ing any service to the engine cooling system.
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, toensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION
OPERATION - HEATER AND AIR CONDITIONER
The heater air conditioner are blend-air type sys-
tems. In a blend-air system, a blend 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 A/C Heater control
panel determines the discharge air temperature by
controlling an electric actuator, which moves the
blend door. This allows an almost immediate control
of the output air temperature of the system.
The mode control knob on the A/C Heater control
panel is used to direct the conditioned air to the
selected system outlets. Both mode control switches
use electric actuators to control the mode doors.
On all vehicles, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a electric actu-
ated recirculation door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a fixed
orifice tube in the liquid line near the condenser out-
let tube to meter refrigerant flow to the evaporator
DRHEATING & AIR CONDITIONING 24 - 1

coil. To maintain minimum evaporator temperature
and prevent evaporator freezing, the A/C Fin Probe
which is located in the evaporator cycles the com-
pressor clutch by sending an A/C request to the
JTEC which in turn processes this piece of informa-
tion and if all conditions are met cycles the compres-
sor clutch.
OPERATION - REFRIGERANT SYSTEM SERVICE
PORT
The low pressure service port is located on the suc-
tion refrigerant line, near the accumulator. The high
pressure service port is located on the liquid line at
the passenger side of the engine compartment, near
the condenser.
Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low humidity air. The evaporator, located in the
HVAC housing on the dash panel below the instru-
ment panel, is cooled to temperatures near the freez-
ing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the air condition-
ing system. When humidity is high, the evaporator
has to perform a double duty. It must lower the air
temperature, and it must lower the temperature of
the moisture in the air that condenses on the evapo-
rator fins. Condensing the moisture in the air trans-
fers heat energy into the evaporator fins and tubing.
This reduces the amount of heat the evaporator can
absorb from the air. High humidity greatly reduces
the ability of the evaporator to lower the temperature
of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Remov-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from the
air conditioning system on humid days. A perfor-
mance test is the best way to determine whether the
system is performing up to standard. This test also
provides valuable clues as to the possible cause of
trouble with the air conditioning system.
Before proceeding, (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - WARNING) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION). The air temperature in
the test room and in the vehicle must be a minimum
of 21É C (70É F) for this test.
(1) Connect a tachometer and a manifold gauge set
or A/C recycling/charging station.
(2) Set the A/C Heater mode control switch knob in
the Recirculation Mode position, the temperature
control knob in the full cool position, and the blower
motor switch knob in the highest speed position.
Fig. 1 HVAC Housing - Dual Zone Shown (Typical -
Single Zone)
1 - Mounting Nut
2 - Passenger Blend Door Actuator (dual zone)
3 - Mounting Nut
4 - Air Intake Spacer
5 - Recirculation Door Actuator
6 - Recirculation Door Assembly
7 - Driver Side Blend Door Actuator
8 - HVAC Housing
9 - Mounting Screw
10 - Defroster Door Actuator
11 - Panel Actuator
24 - 2 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)

Pressure Diagnosis
Condition Possible Causes Correction
4. Air in the refrigerant
system.4. See Plumbing/Diagnosis and Testing -
Refrigerant System Leaks in this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
5. Engine overheating. 5. Refer to Cooling for more information. Test the
cooling system and repair, if required.
The low side pressure is too
high, and the high side
pressure is too low.1. Accessory drive belt
slipping.1. Refer to Cooling for more information. Inspect
the accessory drive belt condition and tension.
Tighten or replace the accessory drive belt, if
required.
2. Fixed orifice tube not
installed.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Faulty compressor. 3. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the fixed orifice tube.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to Cool-
ing for the procedures to check the engine coolant
level and flow, engine coolant reserve/recovery sys-
tem operation, accessory drive belt condition and ten-
sion, radiator air flow and the fan drive operation.
Also be certain that the accessory vacuum supply
line is connected at the engine vacuum source.
MAXIMUM HEATER OUTPUT
Engine coolant is delivered to the heater core
through two heater hoses. With the engine idling at
normal operating temperature, set the temperature
control knob in the full hot position, the mode control
switch knob in the floor position, and the blower
motor switch knob in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged at the HVAC housing floor
outlets. Compare the test thermometer reading to the
Temperature Reference chart.
Temperature Reference
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
DRHEATING & AIR CONDITIONING 24 - 5
HEATING & AIR CONDITIONING (Continued)