Mercedes-Benz Sprinter / Dodge Sprinter. Manual — part 501
Condition
Possible Causes
Correction
The low side pressure is
normal or slightly low, and
the high side pressure is too
low.
1. Low refrigerant system
charge.
1. See 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
A/C evaporator is restricted.
2. See A/C Evaporator in this group. Replace
the restricted A/C evaporator, if required.
3. Faulty A/C compressor.
3. See A/C Compressor in this group. Re-
place 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 re-
stricted.
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. Clean, repair, or
replace components as required.
2. Refrigerant flow through the
receiver/drier is restricted.
2. See Receiver/Drier in this group. Replace
the restricted receiver/drier, if required.
3. Inoperative radiator cooling
fan.
3. Test the radiator cooling fan and replace, if
required. Refer to Group 7 - Cooling.
4. Refrigerant system over-
charged.
4. See Refrigerant System Charge in this
group. Recover the refrigerant from the refrig-
erant system. Charge the refrigerant system
to the proper level, if required.
5. Air in the refrigerant system.
5. See Refrigerant System Leaks in this
group. Test the refrigerant system for leaks.
Repair, evacuate and charge the refrigerant
system, if required.
6. Engine overheating.
6. Test the engine cooling system and repair,
if required. Refer to Group 7 - Cooling.
The low side pressure is too
high, and the high side pres-
sure is too low.
1. Accessory drive belt slip-
ping.
1. Inspect the accessory drive belt condition
and tension. Repair as required. Refer to
Group 7 - Cooling.
2. Faulty A/C expansion valve.
2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Faulty A/C compressor.
3. See A/C Compressor in this group. Re-
place the A/C compressor, if required.
The low side pressure is too
low, and the high side pres-
sure is too high.
1. Restricted refrigerant flow
through the refrigerant lines.
1. See Liquid Line, Suction Line and Dis-
charge Line in this group. Inspect the refriger-
ant lines for kinks, tight bends or improper
routing. Correct the routing or replace the re-
frigerant line, if required.
2. Restricted refrigerant flow
through the A/C expansion
valve.
2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Restricted refrigerant flow
through the A/C condenser.
3. See A/C Condenser in this group. Replace
the restricted A/C condenser, if required.
HEATER PERFORMANCE TEST
Before performing the following tests, perform the
ATC Function Test using the DRBIII
t and refer to
Cooling for the procedures to check the radiator cool-
ant level, serpentine drive belt tension, radiator air
flow and the radiator fan operation.
MAXIMUM HEATER OUTPUT
Engine coolant is provided to the heater core
through a heater valve and heater hose. With the
engine idling at normal operating temperature, set
the heater-A/C controls as follows:
• Temperature control in the full hot position
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HEATING & AIR CONDITIONING
24 - 5
• Mode control in the floor heat position
• Blower motor control in the highest speed posi-
tion
Using a test thermometer, check the temperature
of the air being discharged at the floor outlets. Com-
pare the test thermometer reading to the Tempera-
ture Reference chart.
TEMPERATURE REFERENCE CHART
Ambient Temperature
Minimum Floor Outlet Temperature
Celsius
Fahreheit
Celsius
Fahreheit
15.5°
60°
62.2°
144°
21.1°
70°
63.8°
147°
26.6°
80°
65.5°
150°
32.2°
90°
67.2°
153°
If the floor outlet air temperature is insufficient,
check for a faulty heater valve (perform ATC Func-
tion Test) and verify that the cooling system is oper-
ating to specifications (Refer to 7 - COOLING/
ENGINE/COOLANT - DIAGNOSIS AND TESTING).
Both of the heater hoses should be HOT to the touch
(the coolant return heater hose should be slightly
cooler than the supply hose. If the coolant return
hose is much cooler than the supply hose, locate and
repair the engine coolant flow obstruction in the
heater system.
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
• Pinched or kinked heater hoses.
• Improper heater hose routing.
• Plugged heater hoses or supply and return ports
at the cooling system connections.
• Inoperative or stuck heater water valve.
• Plugged heater core.
If proper coolant flow is verified, and heater floor
outlet air temperature is insufficient, a mechanical
problem may exist.
POSSIBLE LOCATIONS OR CAUSE OF INSUFFI-
CIENT HEAT
• An obstructed cowl air intake.
• Obstructed heater system outlets.
• Heater water valve not functioning properly.
TEMPERATURE CONTROL
If outlet air temperature cannot be adjusted with
the A/C-heater temperature control, one of the follow-
ing could require service:
• Faulty A/C-heater control switch.
• Faulty temperature sensor.
• Faulty A/C-heater control cable or actuator.
• Faulty A/C-heater control module.
ATC FUNCTION TEST
The automatic temperature control (ATC) system
can perform an self-test, which can be activated by
the DRBIII
t scan tool to confirm that the A/C system
is performing satisfactorily. This test provides a
quick confirmation of heating and A/C system perfor-
mance to the service technician. Refer to Body Diag-
nostic Procedures for the appropriate diagnostic
information.
SPECIFICATIONS
HEATING - A / C SYSTEM
FRONT A/C SYSTEM
Item
Description
Notes
A/C Compres-
sor
Denso 7SBU16C
ND-8 PAG oil
Freeze-up Con-
trol
Evaporator tem-
perature sensor
HVAC hous-
ing mounted -
input to A/C-
heater control
- operating
range of -10°
C (14° F) to
40° C (104°
F)
24 - 6
HEATING & AIR CONDITIONING
VA
Item
Description
Notes
Low psi Control
A/C Pressure
Transducer
Liquid line
mounted -
input to PCM
- operating
range of 200
kPa (29 psi)
to 2799 kPa
(406 psi)
High psi Con-
trol
High Pressure
Relief Valve
Receiver/drier
mounted -
opens at a
discharge
pressure over
3999 kPa
(580 psi)
Refrigerant
Charge Capaci-
ty
Refer to the A/C
Underhood Spec-
ification Label
located in the
engine compart-
ment
R-134a refrig-
erant
A/C Clutch Coil
Draw
2.0-3.7 amps @
12V ± 0.5V @
21° C (70° F)
A/C Clutch Air
Gap
0.5 - 0.88 mm
(0.020 - 0.035
in.)
REAR A/C SYSTEM
Item
Description
Notes
A/C Compres-
sor
Denso 10S17
ND-8 PAG oil
Freeze-up Con-
trol
Evaporator Tem-
perature Sensor
Input to rear
A/C control
module -
evaporator fin
mounted -
cycles clutch
off below 1.6°
C (35° F),
cycles clutch
back on
above 3.9° C
(39° F)
Low psi Control
A/C Low Pres-
sure Switch
Input to rear
A/C control
module - suc-
tion line
mounted -
cycles clutch
off below 30
kPa (4.4 psi)
Item
Description
Notes
High psi Con-
trol
A/C High Pres-
sure Switch
Input to rear
A/C control
module - con-
denser inlet
tube mounted
- cycles clutch
off above
2551 kPa
(370 psi)
Refrigerant
Charge Capaci-
ty
Refer to the Rear
A/C Specification
Label
R-134a refrig-
erant
A/C Clutch Coil
Draw
3.3 amps @ 12V
± 0.5V @ 21° C
(70° F)
A/C Clutch Air
Gap
0.35 - 0.60 mm
(0.014 - 0.024
in.)
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HEATING & AIR CONDITIONING
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CONTROLS - FRONT
TABLE OF CONTENTS
page
page
A/C COMPRESSOR CLUTCH
. . . . . . . . . . . . . . . . . . . . . . . . . . 8
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
A/C COMPRESSOR CLUTCH BREAK-IN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . . . . . . . . . . . . . . . . . . . . . . 11
. . . . . . . . . . . . . . . . . . . . . . . . . 11
A/C COMPRESSOR CLUTCH COIL
A/C HEATER CONTROL
. . . . . . . . . . . . . . . . . . . . . . . . . 12
. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
. . . . . . . . . . . . . . . . . . . . . . . . . 13
A/C PRESSURE TRANSDUCER
. . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . 14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
. . . . . . . . . . . . . . . . . . . . . . . . . 15
AIR OUTLET TEMPERATURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 16
. . . . . . . . . . . . . . . . . . . . . . . . . . . 16
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
. . . . . . . . . . . . . . . . . . . . . . . . . 16
AMBIENT TEMPERATURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . . . . . . . . 17
BLOWER MOTOR RESISTOR
. . . . . . . . . . . . . . . . . . . . . . . . . 17
. . . . . . . . . . . . . . . . . . . . . . . . . . . 18
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
. . . . . . . . . . . . . . . . . . . . . . . . . 18
BLOWER MOTOR SWITCH
. . . . . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . 19
EVAPORATOR TEMPERATURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
. . . . . . . . . . . . . . . . . . . . . . . . . 20
IN-CAR TEMPERATURE SENSOR
. . . . . . . . . . . . . . . . . . . . . . . . . 21
. . . . . . . . . . . . . . . . . . . . . . . . . . . 21
MODE DOOR CABLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
. . . . . . . . . . . . . . . . . . . . . . . . . 21
RECIRCULATION DOOR ACTUATOR
. . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
. . . . . . . . . . . . . . . . . . . . . . . . . 23
A / C COMPRESSOR CLUTCH
DESCRIPTION
The A/C compressor clutch assembly consists of a
stationary electromagnetic field coil, a hub bearing
and pulley assembly, and a clutch plate (Fig. 1). The
field coil and the hub bearing and pulley assembly
are each retained on the nose of the compressor front
housing with snap rings. The clutch plate is splined
to the compressor shaft and secured with a bolt.
The compressor clutch plate and pulley and the
clutch field coil are available for service replace-
ment.
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CONTROLS-FRONT
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