1993 DODGE TRUCK refrigerant type

•
• —• •
HEATING
AND AIR
CONDITIONING
24 - 1 CONTENTS

page

CLIMATE CONTROL SYSTEM
............. 21
REFRIGERANT SYSTEM SERWICE

COMPRESSOR
SERWICE
(SD-709)
......... 21
PROCEDURES
.............
DIAGNOSTIC PROCEDURES
3
TORQUE SPECIFICATIONS
GENERAL INFORMATION
1
page

. 17
. 31
GENERAL INFORMATION

HEATER SYSTEM
All models use a Blend-Air type heater. Outside air
enters the heater through the cowl opening and
passes through a plenum chamber to the heater core. Air intake openings must be kept free of snow, ice and other obstructions for the heater system to pick
up sufficient outside air. A temperature control door
in the heater housing directs incoming air through
the heater core and/or the heater core bypass. The amount of blend (heated and non-heated air) is deter­
mined by the setting of the temperature lever on the
instrument panel. Direction of the blended air is con­
trolled by the HEAT-DEFROST lever on the instru­ ment panel. The blower switch and resistor block controls the
speed of the blower motor. This in turn controls the
velocity of the air flow from the heater outlets. The resistor block consists of 2 helical wound wire
resistors connected to terminals which are mechani­ cally attached to a glass-filled phenolic board. This
assembly is bolted to the plenum. The blower switch controls the blower motor speed
by selectively connecting the resistors in series to the
blower motor.
A self-adjusting clip, on each of 2 control cables has
been incorporated to simplify cable adjustment. This clip snaps onto the control cable core wire and will slide along the wire under a specific load to provide
an automatic cable adjustment.

AIR
CONDITIONING
SYSTEM
Air intake openings must be kept free of snow, ice
and other obstructions for the air conditioning sys­
tem to pick up sufficient outside air.

COMPONENTS

• COMPRESSOR-The seven piston SD-709 com­
pressor is used on all vehicles. This compressor com­
presses the low pressure refrigerant vapor into a high pressure, high temperature vapor. • CLUTCH PULLEY AND COIL-These are
mounted on the compressor, providing a convenient
way to drive it and disengage it in accordance to the cooling needs.
• CONDENSER-The condenser is located in front
of the radiator. Its function is to cool the hot, high
pressure refrigerant gas causing it to condense into
high pressure liquid refrigerant.
• FILTER-DRIER—The filter-drier is used to remove
any traces of moisture from the refrigerant system.
This component incorporates the sight glass and the
high pressure relief valve.
• SIGHT GLASS-The sight glass is provided as a
diagnostic tool to observe refrigerant flow and indi­ cate refrigerant level. It is located at the top of the
filter drier.
• HIGH -PRESSURE RELIEF VALVE-This is a safety device designed to open automatically if the
system pressure reaches a predetermined level. This
will prevent system component damage. • EXPANSION (H) VALVE-The expansion (H)
valve is used to meter refrigerant into the evaporator
in accordance with cooling requirements. • EVAPORATOR COIL-The evaporator coil is lo­
cated in the A/C unit. Its function is to cool and de-
humidify the air before it enters the vehicle. • FREEZE CONTROL-The main function of freeze
control is to prevent water on the evaporator coil face
from freezing which restricts the airflow. An elec­
tronic temperature cycling switch is located on the
refrigerant plumbing (suction line) near the H-Valve.
The switch turns the compressor ON-OFF depending
on the temperature in the suction line. The switch is a sealed, specially calibrated unit. If found defective,
the switch must be replaced. • REFRIGERANT LINES-These lines are needed
to carry the refrigerant between the various system components.
• CONDENSATE DRAIN TUBE-Condensation
which accumulates on the bottom of the evaporator

HEATING
AND AIR
CONDITIONING

24 - 8
HEATING
AND AIR
CONDITIONING

• (e) If compressor clutch cycles 3 to 10 times per
minute with temperature between 20°C-32°C (68°F-
90°F),
the cycling switch is normal. If the compressor
clutch fails to engage, check for continuity in the elec­
trical circuit. Above 32°C (90°F) the compressor clutch
may be continuously engaged (non-cycling) due to the
high heat load. This condition is normal.
(4)
Refer to the Evaporator Heater Assembly for
the Removal/Installation procedures.

TESTING
THE
SYSTEM
FOR
LEAKS
If the air conditioning system is not cooling properly,
check that the refrigerant system is fully charged with

R-12.
Follow the procedures in the Sight Glass Refrig­
erant Level Test section of this group.
If the refrigerant system is empty or low in refrig­
erant charge, a leak at any of the line fittings or
component seals is likely (Fig. 4). To detect a leak in
the refrigerant system, perform one of the following
procedures as indicated by the symptoms.

ELECTRONIC
TEMPERATURE CYCLING

SWITCH
EXPANSION

"H"
VALVE

J9324-96
Fig.
4 Testing for
Leaks

EMPTY REFRIGERANT SYSTEM LEAK TEST
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible.
(2) Prepare a 14 oz. refrigerant (R-12) charge to be
injected into the system. (3) Connect and dispense 14 ozs. of refrigerant (R-
12) into the evacuated refrigerant system, (4) Proceed to Step 2 of Low Refrigerant Level
Leak Test.

LOW REFRIGERANT LEVEL LEAK TEST
(1) Review the Safety Precautions section of this
group to determine if there is still R-12 in the refrig­
erant system. (2) Position the vehicle in a breeze free work area
to make it less difficult to detect a small leak. (3) With the engine not running, use an Electronic
Leak Detector, or equivalent, to search for leaks in
the most accessible areas first.
(a) Fittings, lines, or components that appear
oily usually will implicate a refrigerant leak.
(b) To inspect the evaporator core for leaks, it is
possible to insert the leak detector probe into the opening on the right side of the instrument panel.
COMPRESSOR OIL LEVEL It is important to have the correct amount of oil in
the A/C system to ensure proper lubrication of the compressor. Too little oil will result in damage to the
compressor. Too much oil will reduce the cooling ca­
pacity of the system and consequently result in
higher discharge air temperatures.
To provide the desired balance for adequate lubri­
cation and cooling capacity, each compressor is
charged with 135 ml (4.6 oz.) of oil at the factory.
The oil used in the compressors is a 500 SUS vis­
cosity, wax-free refrigerant oil. Only refrigerant oil of the same type should be used to service the sys­
tem. Do not use any other oil. The oil container should be kept tightly capped until it is ready for

use,
and then tightly capped after use to prevent en­
trance of dirt and moisture. Refrigerant oil will quickly absorb any moisture it comes in contact with.
After the compressor has been installed and operated
in the A/C system, the oil will be distributed through­
out the system. Some of the oil will be trapped by com­
ponents in the system. An equivalent amount of oil
must be added to the system to compensate for the
trapped oil when replacing the following: • Evaporator Coil: 59.2 ml (2 oz.)
• Condenser: 30 ml (1 oz.)
• Filter-Drier: 30 ml (1 oz.) 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. Replacement compressors are also charged with
135 ml (4.6 oz.). When replacing compressor; remove,
drain oil, measure amount and discard old oil. For
the replacement compressor use the same amount of refrigerant oil as recovered from the failed compres­sor. This adjustment is not needed if the system has
been flushed, removing retained oil. The Compressor Oil Level Adjustment Chart
should be followed to determine the need to perform
an oil level adjustment. Check oil level (basic fill) as follows: (1) Slowly discharge complete system.
(2) With system discharged, disconnect suction and
discharge lines and remove compressor. Drain and dis­ card oil through suction port and discharge port on top.

•

HEATING
AND
AIR
CONDITIONING
24-17 REFRIGERANT SYSTEM SERWICE PROCEDURES

INDEX
page
Charging
the
System
19

Correcting
Low
Refrigerant
Level
.............
20
Discharging
the
System
. 19
Evacuating
the
System
19

REFRIGERANT

SAFETY
PRECAUTIONS

WARNING: EXTREME CARE MUST
BE
TAKEN
TO
PREVENT
ANY LIQUID
REFRIGERANT FROM COM­
ING
IN
CONTACT
WITH
THE
SKIN
AND
ESPE­

CIALLY
THE
EYES.
ALWAYS WEAR SAFETY
GOGGLES WHEN SERVICING
ANY
PART
OF
THE
REFRIGERANT SYSTEM.
IF EYE
CONTACT
IS

MADE,
APPLY
A
FEW
DROPS
OF
MINERAL
OIL
TO

THE
EYES
AND
FLUSH
WITH
WATER
FOR
SEV­
ERAL MINUTES.
SEEK
MEDICAL
ATTENTION
IMME­
DIATELY.

The refrigerant used
in the air
conditioner system
is Refrigerant-12 (R-12).
R-12 is
nonexplosive, non­
flammable, non-corrosive,
has
practically
no
odor
and
is heavier than
air.
Although
it is
classified
as a
safe
refrigerant, certain precautions must
be
observed
to

protect
the
parts involved
and the
person
who is

working
on the
unit. Liquid
R-12, at
normal atmo­ sphere pressures
and
temperatures, evaporates
so

quickly that
it has the
tendency
to
freeze anything
it
contacts.

WARNING:
TO
AVOID
A
DANGEROUS EXPLOSION,
NEVER
WELD
OR
STEAM CLEAN NEAR
AIR
CON­

DITIONING
LINES
OR
COMPONENTS.
DO NOT

HEAT
R-12
ABOVE
52°C (125°F)
BECAUSE
THE

CAN
MAY
EXPLODE.

The
R-12 in the
system
is
always under pressure.
Because
the
system
is
tightly sealed, heat applied
to
any part could cause this pressure
to
build
up
exces­sively.

WARNING: LARGE AMOUNTS
OF
REFRIGERANT
RELEASED
IN A
CLOSED WORK AREA
WILL
DIS­
PLACE
THE
OXYGEN
AND
CAUSE SUFFOCATION.
ALWAYS
MAINTAIN
GOOD
VENTILATION
SUR­ ROUNDING
THE
WORK AREA.

R-12
gas,
under normal conditions,
is
non-poison­

ous.
The
discharge
of R-12 gas
near
an
open flame
page
Pressure Gauge
and
Manifold
Assembly
18

Refrigerant
. 17

Refrigerant
Leak Repair Procedure
20

Service Precautions
. 17

can produce
a
very poisonous
gas
called phosgene.
Phosgene
is
generated when
a
flame-type leak detec­
tor
is
used.

CAUTION:
When charging
an A/C
system always
keep
the
tank
in an
upright position.
If the
tank
is

on
its
side
or
upside down,
liquid
refrigerant
will

enter
the
system
and may
damage
the
compressor.

In most instances, moderate heat
is
required
to

bring
the
pressure
of the
refrigerant above system
pressure when charging
or
adding refrigerant.
A

bucket
or
large
pan of hot
water,
not
over 52°C (125°F),
is all the
heat required
for
this purpose.
Do

not heat
the
refrigerant container with
a
blow torch
or
any
other means that would raise
the
temperature and pressure above this temperature.

CAUTION:
Do not
allow
liquid
refrigerant
to
touch
bright
metal.

Refrigerant will tarnish bright metal
and
chrome
surfaces. Avoid splashing
the
refrigerant
on any
sur­

face.
Refrigerant
in
combination with moisture
is

very corrosive
and can
cause extensive damage
to all

metal surfaces.

RECYCLING
(R-12) refrigerant
is a
chloroflorocarbon
(CFC)
that
can contribute
to the
depletion
of the
ozone layer
in

the upper atmosphere. Harmful radiation from
the
sun
is
filtered
out by the
ozone.
To
assist
in
protect­
ing
the
ozone layer, Chrysler Corporation recom­
mends that
an
(R-12) refrigerant recycling device
that meets
SAE
standard
J1991 be
used. Contact
an
automotive service equipment supplier
for
refriger­
ant recycling equipment that
is
available
in
your
area. Refer
to the
operating instructions provided
with
the
recycling equipment
for
proper operation.

SERVICE
PRECAUTIONS
Kinks
in the
refrigerant tubing
or
sharp bends
in

the refrigerant hose lines will greatly reduce
the ca­
pacity
of the
entire system. High pressures
are
pro­duced
in the
system when
it is
operating. Extreme
care must
be
exercised
to
make sure that
all
connec­
tions
are
pressure tight. Dirt
and
moisture
can
enter

•

HEATING
AND
AIR
CONDITIONING
24 - 19
Connect
the
compound gauge hose
to the
compres­
sor suction service valve gauge port (low-side).
Connect
the
high pressure gauge hose
to the
dis­
charge service valve gauge port (high-side). Purge
air
from
the
high side test hose
by
opening
the high side hand valve
on the
manifold
for 3 to 5
seconds.
The
center connection
on the
manifold must
be open.
Purge
air
from
the low
side test hose
by
opening
the
low
side hand valve
on the
manifold
for 3 to 5
seconds.
The
center connection
on the
manifold must
be open.
The
air
conditioning system
may be
operated with
the gauge manifold assembly connected
in
this man­
ner.
The
gauges will indicate respective operative
pressures.

DISCHARGING
THE SYSTEM
Since
the air
conditioning refrigerant system
is

pressurized,
it
will
be
necessary
to
completely dis­ charge
the
system before replacing
any
refrigerant
components.
The
procedure
is as
follows: (1) Install gauge
set as
described under manifold
gauge
set
installation. Make sure
the
gauge
set

valves
are
closed before attaching
the
hoses
to the re­

frigerant system. (2) Install
a
long hose
to the
manifold gauge
set

connector.
Run
this hose
to the oil
collector
can
near
the shop exhaust system. A good
oil
collector
can may be
made from
a
large
empty coffee
can
with
a
plastic
top.
Slit
the
plastic
top
in the
form
of a Y to
make
an
entrance
for the
refrigerant hose
and
exit
for the gas.
(3) Open
the
compressor discharge
and
suction line
pressure valves
and
discharge
the
refrigerant into
the
oil
collector
can.
Watch
to
make sure
the
hose does
not
blow
out of the
collector
can.
(4) When
the
system
has
been completely dis­
charged, measure
the
amount
of oil
collected
in the

can.
The
amount
of oil
measured should
be
added
to

the refrigerant system before
it is
charged. Discard
the used
oil. Add new oil.

EVACUATING
THE SYSTEM
Whenever
the
system
has
been opened
to the
atmo­
sphere,
it is
absolutely essential that
the
system
be

evacuated
to
remove
all the air and
moisture.
Air in

the refrigerant system causes high compressor dis­ charge pressures,
a
loss
in
system performance,
and

oxidation
of the
compressor
oil
into
gum and
varnish.
Moisture
in the
refrigerant system
can
cause
the ex­

pansion valve
to
malfunction. Under certain condi­
tions
it can
react with
the
refrigerant
to
form destructive acids.
It is
necessary
to
adhere
to the
fol­
lowing procedure
to
keep
air and
moisture
out of the
system. (1) Connect
the
manifold gauge
set to the
compres­
sor
and
long test hose from manifold gauge
set
center
connection
to
Vacuum Pump Tool C-4289. (2) Open both manifold gauge
set
valves.
(3) Start
the
vacuum pump
and
operate until
the

evaporator suction gauge registers
at
least
-88
kPag (26 inches
of
vacuum).
If at
least
-88
kPag
(26
inches
of vacuum) cannot
be
obtained, either
the
system
has

a leak
or the
vacuum pump
is
defective. Check
the

vacuum pump.
If the
pump proves
to be
functioning
properly,
the
system
has a
leak. Charge
the
system
with
1
pound
of
refrigerant. Locate
and
repair
all
leaks.
Discharge
the
refrigerant
and
evacuate
the
system.
(4) Continue
to
operate
the
pump
for at
least
5

minutes.
(5) Close manifold valves. Turn
off the
vacuum
pump
and
observe evaporator suction gauge
for 2
minutes.
The
vacuum level should remain constant.
If
the
vacuum level falls
off, the
system
has a
leak. Charge
the
system with
450 g (1
pound)
of
refriger­
ant. Locate
and
repair
all
leaks. Discharge
the
sys­
tem
and
repeat evacuation procedure.

CHARGING
THE
SYSTEM
The refrigerant system must have been evacuated
using
the
previous procedure before charging. Charge
using only
R-12
refrigerant.
R-12 is
available
in
bulk
tanks
or 437 g (14 oz.)
cans. The special refrigerant dispensing manifold per­
mits charging
3
cans
of
refrigerant
at a
time. When
using disposable cans
of
this type, carefully follow
the
can
manufacturers instructions.

WARNING: NEVER USE THESE CANS
TO
CHARGE
INTO
THE
HIGH
PRESSURE SIDE
OF
THE
SYSTEM

(COMPRESSOR
DISCHARGE PORT)
OR
INTO
A
SYSTEM
THAT
IS AT
HIGH
TEMPERATURE.
THE
HIGH
SYSTEM PRESSURES COULD
BE
TRANS­

FERRED
INTO
THE
CHARGING
CAN
CAUSING
IT

TO EXPLODE.

Keep
the
refrigerant manifold valves capped when
not
in use.
Keep
a
supply
of
extra refrigerant-can-to
refrigerant-manifold gaskets
on
hand
so the
gaskets can
be
replaced periodically. This will insure
a
good
seal without excessive tightening
of the can or the

manifold nuts.
(1) Attach center hose from manifold gauge
set to

refrigerant dispensing manifold. Turn refrigerant manifold valves completely counterclockwise
so
they are fully open. Remove protective caps from refriger­
ant manifold.
(2) Screw refrigerant cans into manifold.
Be
sure
manifold-to-can gasket
is in
place
and in
good condi­
tion. Tighten
can and
manifold nuts
to 9.5 N»m (7 ft.
lbs.) torque.