Dodge Dakota (R1). Manual — part 789
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 21° C (70° F) for this test. Also the fin probe (locat-
ed in the evaporator of the HVAC unit) must be a
minimum of 65° for this test as well.
(1) Connect a tachometer and a manifold gauge
set.
(2) Set the a/c heater control to the recirculation
mode (Max-A/C) position, the temperature control
knob in the full cool position, and the blower motor
switch knob in the highest speed position.
(3) Start the engine and hold the idle at 1,000 rpm
with the compressor clutch engaged. If the compres-
sor does not engage, see the A/C Diagnosis chart in
the Diagnosis and Testing section of this group.
(4) The engine should be at operating temperature.
The doors and windows must be closed.
(5) Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the a/c system until it
stabslizes.
(6) With the compressor clutch engaged, record the
discharge air temperature, the condenser out pres-
sure (high side), and the compressor inlet pressure
(low side). The compressor clutch may cycle, depend-
ing upon the ambient temperature and humidity. If
the clutch cycles, use the readings obtained before
the clutch disengaged.
(7) Compare the discharge air temperature read-
ing to the Performance Temperature and Pressure
chart. If the temperature reading is high, clamp off
both heater hoses (inlet and outlet), wait five min-
utes and record the temperature again. Compare the
second reading to the Performance Temperature and
Pressure chart. If the temperature reading is now
OK, see A/C Diagnosis chart for normal pressures. Or
see A/C Performance Test if air temperatures are too
high,
(8) Compare the discharge (high side) and suction
(low side) pressure readings to the Performance Tem-
perature and Pressure chart. If the pressures are
abnormal, see (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - DIAGNOSIS AND TEST-
ING - REFRIGERANT SYSTEM LEAKS) and (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE).
Performance Temperature and Pressure
Ambient Air Temperature
21°C
(70°F)
27°C
(80°F)
32°C
(90°F)
38°C
(100°F)
43°C
(110°F)
Maximum Allowable Air
Temperature at Center Panel
Outlet
7°C
(45°F)
7°C
(45°F)
13°C
(55°F)
13°C
(55°F)
18°C
(64°F)
Compressor Inlet Pressure at
Service Port (Low Side)
138 to 207
kPa
(20 to 30 psi)
172 to 241
kPa
(25 to 35 psi)
207 to 276
kPa
(30 to 40 psi)
241 to 310
kPa
(35 to 45 psi)
276 to 345
kPa
(40 to 50 psi)
Condensor Out Pressure at
Service Port (High Side)
1034 to 1724
kPa
(150 to 250
psi)
1379 to 2068
kPa
(200 to 300
psi)
1724 to 2413
kPa
(250 to 350
psi)
1999 to 2689
kPa
(290 to 390
psi)
2413 to 2965
kPa
(350 to 430
psi)
(9) Compare the compressor discharge and suction
(evaporator inlet) pressure readings to the Perfor-
mance Temperature and Pressure chart. If the com-
pressor discharge pressure or suction pressure is not
normal, see the Pressure Diagnosis chart.
24 - 2
HEATING & AIR CONDITIONING
AN
HEATING & AIR CONDITIONING (Continued)
A/C Diagnosis
Condition
Possible Causes
Correction
Rapid compressor clutch
cycling (ten or more cycles
per minute).
1. Low refrigerant system
charge.
1. See Refrigerant System Leaks in the Diagnosis
and Testing section of this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
2. Faulty Evaporator.
2. See Evaporator Temperature Sensor in the
Diagnosis and Testing section of this group. Test
the Evaporator Temperature Sensor.
3. Faulty Powertrain Control
Module (PCM)
3. Refer to the proper Diagnosis Procedurers
manual for testing of the PCM. Test the PCM and
replace, if required.
4. Faulty Pressure
Transducer
4. See Pressure Transducer Diagnosis and
Testing in this section.
5. Faulty Loss of Charge
Pressure Switch
5. See Loss of Charge Pressure Switch
Diagnosis and Testing in this section
Equal pressures, but the
compressor clutch does not
engage.
1. No refrigerant in the
refrigerant system.
1. (Refer to 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.
2. Faulty fuse.
2. Check the fuses in the Power Distribution
Center and the junction block. Repair the shorted
circuit or component and replace the fuses, if
required.
3. Faulty a/c compressor
clutch coil.
3. (Refer to Controls/A/C Compressor Clutch
Coil/Diagnosis and Testing) in this group. Test the
compressor clutch coil and replace, if required.
4. Faulty a/c compressor
clutch relay.
4. (Refer to Controls/A/C Compressor Clutch
Relay/Diagnosis and Testing) in this group. Test
the compressor clutch relay and relay circuits.
Repair the circuits or replace the relay, if
required.
5. Faulty evaporator
temperature sensor.
5. (Refer to Controls/A/C Low Pressure
Switch/Diagnosis and Testing) in this group. Test
the a/c low pressure switch and tighten or
replace, if required.
6. Faulty loss of charge
pressure switch.
6. (Refer to Controls/A/C Pressure Transducer/
Diagnosis and Testing) in this group. Test the a/c
pressure transducer and replace, if required.
7. Faulty Power Train Control
Module.
7. (Refer to Appropriate Diagnostic Information)
for testing of the PCM. Test the PCM and
replace, if required.
8. Faulty pressure
transducer.
8. Refer to Diagnosis and Testing Faulty Pressure
Transducer in the section.
9. Faulty heater-A/C control.
9. Refer to Faulty heater-A/C Control in this
section.
AN
HEATING & AIR CONDITIONING
24 - 3
HEATING & AIR CONDITIONING (Continued)
A/C Diagnosis
Condition
Possible Causes
Correction
Normal pressures, but A/C
Performance Test air
temperatures at center panel
outlet are too high.
1. Excessive refrigerant oil in
system.
1. (Refer to Plumbing/Refrigerant Oil/Standard
Procedure/Refrigerant Oil Level) in this group.
Recover the refrigerant from the refrigerant
system and inspect the refrigerant oil content.
Restore the refrigerant oil to the proper level, if
required.
2. Blend door actuator
inoperative or faulty.
2. Check the Blend Door Actuator operation.
Replace as required.
3. Blend door inoperative or
sealing improperly.
3. (Refer to Distribution/Blend Door/Removal/
Installation) in this group. Inspect the blend door
for proper operation and sealing and correct, if
required.
4. Faulty evaporator.
4. Refer to evaporator section.
The low side pressure is
normal or slightly low, and
the high side pressure is too
low.
1. Low refrigerant system
charge.
1. (Refer to 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.
2. Refrigerant flow through
the accumulator is restricted.
2. (Refer to Plumbing/Accumulator/Removal/
Installation in this group. Replace the restricted
accumulator, if required.
3. Refrigerant flow through
the a/c evaporator is
restricted.
3. (Refer to Plumbing/A/C Evaporator/Removal/
Installation in this group. Replace the restricted
a/c orator, if required.
4. Faulty a/c compressor.
4. (Refer to Plumbing/A/C Compressor/Removal/
Installation in this group. Replace the a/c
compressor, if required.
The low side pressure is
normal or slightly high, and
the high side pressure is too
high.
1. A/C condenser air flow
restricted.
1. Check the a/c condenser for damaged fins,
foreign objects obstructing air flow through the
condenser fins, and missing or improperly
installed air seals. Refer to Cooling for more
information on air seals. Clean, repair, or replace
components as required.
2. Inoperative cooling fan.
2. Refer to Cooling for more information. Test the
cooling fan and replace, if required.
3. Refrigerant system
overcharged.
3. (Refer to Plumbing/Standard Procedure -
igerant System Charge) in this group. Recover
the refrigerant from the refrigerant system.
Charge the refrigerant system to the proper level,
if required.
4. Air in the refrigerant
system.
4. (Refer to 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.
6. Faulty orifice tube.
6. Refer to orifice tube section.
24 - 4
HEATING & AIR CONDITIONING
AN
HEATING & AIR CONDITIONING (Continued)
A/C Diagnosis
Condition
Possible Causes
Correction
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. A/C orifice tube not
installed.
2. (Refer to Plumbing/A/C Orifice Tube) in this
group. Install the missing fixed orifice tube, if
required.
3. Faulty a/c compressor.
3. (Refer to Plumbing/A/C Compressor/Removal/
Installation 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. (Refer to Plumbing/Caution - Refrigerant
Hoses/Lines/Tubes Precaution) 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 a/c orifice tube.
2. (Refer to Plumbing/A/C Orifice Tube) in this
group. Replace the restricted fixed orifice tube, if
required.
3. Restricted refrigerant flow
through the a/c condenser.
3. (Refer to Plumbing/A/C Condenser) in this
group. Replace the restricted a/c condenser, if
required.
4. Restricted Filter Drier.
4. See Filter-Drier in the Removal and Installation
section of the group. Replace the restricted
Filter-Drier, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE
Before performing the following tests, refer to
Group 7 – Cooling System for the procedures to
check the engine coolant level and flow, engine cool-
ant
reserve/recovery
system
operation,
accessory
drive belt condition and tension, radiator air flow
and the fan drive operation.
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 Temperature
15.5° C
(60° F)
21.1° C
(70° F)
26.6° C
(80° F)
32.2° C
(90° F)
Minimum Air Temperature at
Floor Outlet
52.2° C
(126° F)
56.1° C
(133° F)
59.4° C
(139° F)
62.2° C
(144° F)
AN
HEATING & AIR CONDITIONING
24 - 5
HEATING & AIR CONDITIONING (Continued)
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст