1999 DODGE RAM oil pressure


A/C -H EA TE R S YSTE M T R O UBLE S H O OTIN G

1999 D odge P ic ku p R 1500
1999 MANUAL A/C-HEATER SYSTEMS
Trouble Shooting - Cars & Trucks
CHRYSLER
Avenger, Breeze, Caravan, Cirrus, Concorde, Dakota, Durango,
Intrepid, LHS, Neon, Ram Pickup, Ram Van/Wagon, Sebring Convertible,
Sebring Coupe, Stratus, Town & Country, Voyager, 300M
A/C SYSTEM DIAGNOSIS
RAPID COMPRESSOR CLUTCH CYCLING
Some possible causes of rapid compressor clutch cycling,
clutch cycles 10 or more times per minute, include:
* Low refrigerant system charge.
* Faulty low pressure cycling clutch switch.
* Faulty PCM.
COMPRESSOR WILL NOT ENGAGE
Some possible causes of compressor not engaging with high and
low side system pressures equal include:
* No refrigerant in system.
* Faulty fuse.
* Faulty compressor clutch coil.
* Faulty compressor clutch relay.
* Faulty electronic cycling clutch switch.
* Improperly installed or faulty low pressure cycling clutch
switch.
* Faulty low pressure cut-off switch.
* Faulty high pressure cut-off switch.
* Faulty PCM.
* Faulty A/C-heater control panel.
TEMPERATURE IS TOO HIGH WITH A/C ON
Some possible causes of high temperature output at center
panel when A/C system pressure is normal include:
* Excessive oil charge in refrigerant.
* Temperature control cable improperly installed or faulty.
* Blend-air door inoperative, obstructed or sealing
improperly.
* Blend door actuator not calibrated.
LOW SIDE PRESSURE IS LOW-TO-NORMAL & HIGH SIDE PRESSURE IS
LOW
Some possible causes of low side system pressure being lower-
to-normal and high side system pressure being too low include:
* Low refrigerant system charge.
* Refrigerant flow through accumulator is restricted.
* Refrigerant flow through evaporator is restricted.
* Faulty compressor.
LOW SIDE PRESSURE IS HIGH-TO-NORMAL & HIGH SIDE PRESSURE IS

Refrigerant R-12 based systems use mineral oil, while R-134a
systems use synthetic Polyalkylene Glycol (PAG) oils. Using a mineral
oil based lubricant with R-134a will result in A/C compressor failure
due to lack of proper lubrication.
Following are the most common R-134a refrigerant oils used by
most domestic vehicles:
Chrysler Corp., Eagle & Jeep
Use ND-8 PAG oil, SUN PAG 56 oil, SP-10 PAG Oil, or SP-20 PAG
oil.
Ford Motor Co.
Use YN-12B or YN-12C PAG Refrigerant Oil (specification WSH-
M1C231-B) or SP-20 PAG Oil (specification WST-M1C231-B2).
General Motors
On all models except Saturn, use PAG Refrigerant Oil (Part
No. 12345923). On Saturn, use Saturn PAG refrigerant oil.
NOTE: PAG oil absorbs moisture very rapidly, 2.3-5.6 percent by
weight as compared to a mineral oil absorption rate of .005
percent by weight.
NOTE: Use ONLY the specified oil for the appropriate system or A/C
compressor. Always check the underhood A/C specification
label or A/C compressor label before adding refrigerant oil
to A/C system.
SYSTEM SERVICE VALVES
SCHRADER-TYPE VALVES
NOTE: Although similar in construction and operation to a tire
valve, NEVER replace a Schrader-type valve with a tire
valve.
Schrader valve is similar in construction and operation to a
tire valve. See Fig. 4. When a test gauge hose is attached (hose has
built-in valve core depressor), Schrader stem is pushed inward to the
open position and allows system pressure to reach the gauge.
If test hose being used does not have a built-in core
depressor, an adapter must be used. Never attach hoses or adapters to
a Schrader valve unless it is first connected to manifold gauge set.
Fig. 4: Schrader Service Valve (Compressor Location Shown)
SPECIAL VALVE CONNECTORS
On some General Motors models, thread size on high-side

ORIFICE TUBE REPLACEMENT
CHRYSLER CORP.
Removal & Installation (Dakota)
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
liquid line at condenser outlet tube. Cover open refrigerant fittings
to protect from moisture and dirt.
2) Using 2 wrenches, loosen tube fitting and separate front
half of liquid line from rear half of liquid line. Using needle nose
pliers, remove fixed orifice tube from rear half of liquid line. Note
fixed orifice tube orientation for correct installation.
3) To install, reverse removal procedure. Ensure fixed
orifice tube is positioned correctly. Evacuate, charge, and leak test
A/C system. Ensure A/C system operates properly.
NOTE: On Ram Pickup, if the fixed orifice tube is faulty or
plugged, the liquid line and orifice tube must be replaced as
an assembly.
Removal & Installation (Ram Pickup)
Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
liquid line from evaporator inlet and condenser outlet tubes. Cover
open refrigerant fittings to protect from moisture and dirt.
Disconnect liquid line retaining clips. Remove liquid line and orifice
tube. To install, reverse removal procedure. Evacuate, charge, and
leak test A/C system. Ensure A/C system operates properly.
FORD MOTOR CO.
NOTE: Replace orifice tube whenever compressor is replaced. Fixed
orifice tube is located in the condenser-to-evaporator liquid
line.
NOTE: DO NOT use pliers to remove fixed orifice tube or twist
orifice tube in liquid line. Doing so will cause plastic
orifice tube body to break inside condenser-to-evaporator
liquid line.
Fixed Orifice Tube Replacement (Except Continental, Mustang &
Villager)
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. On Contour
and Mystique, move power steering fluid reservoir to one side without
disconnecting hoses.
2) On all models, disconnect condenser-to-evaporator
discharge (liquid) line. Remove and discard "O" rings from line. Pour
a small amount of refrigerant oil into inlet to lubricate orifice "O"
rings.
3) Insert orifice tube remover/installer into tube and turn
tool to right to engage tangs on orifice tube. See Fig. 18. Hold "T"
handle of tool and slowly tighten nut down onto discharge line to
slowly pull orifice tube out. If orifice tube breaks off when removal
is attempted, use orifice tube extractor to pull the broken section
out. See Fig. 19.
4) Ensure replacement orifice tube is fitted with "O" ring(s)\
lubricated with clean refrigerant oil. Insert tube with short end
toward evaporator, until seated. Reconnect high pressure line. On
Contour and Mystique, tighten connection to 18 ft. lbs. (24 N.m).

evaporator inlet line and "O" rings with refrigerant oil. Lubricate
orifice tube and "O" ring with refrigerant oil. Insert orifice tube
into evaporator inlet line with short screen toward condenser.
2) Tighten liquid line nut to 18 ft. lbs. (24 N.m). To
complete installation, reverse removal procedure. Evacuate, charge,
and test system for proper operation.
Removal ("F" Body)
Discharge A/C system, using approved recovery/recycling
equipment. Disconnect negative battery cable. Disconnect A/C pressure
switch connector. Use a backup wrench to hold evaporator fitting, and
loosen evaporator liquid line fitting. Remove bolt. Disconnect
evaporator liquid line. Remove and discard "O" rings. Using needle-
nose pliers, remove orifice tube from evaporator inlet line.
Installation
1) Clean evaporator line fitting with refrigerant oil. Coat
inside of inlet line and evaporator line "O" rings with refrigerant
oil. Lubricate orifice tube and "O" ring with refrigerant oil and
insert them into inlet line. Insert orifice tube into evaporator inlet
line with long screen inlet end toward condenser.
2) Tighten bolt to 12 ft. lbs. (16 N.m). Tighten evaporator
line fitting to 28 ft. lbs. (38 N.m). To complete installation,
reverse removal procedure. Evacuate, charge, and test system for
proper operation.
Removal ("J" & "N" Body)
1) Locate orifice tube. See ORIFICE TUBE LOCATION &
REMOVER/INSTALLER APPLICATION table. Discharge A/C system, using
approved recovery/recycling equipment. On "J" body, remove upper
closeout panel. On "N" body, raise and support vehicle. On all models,
disconnect condenser-to-evaporator line at condenser outlet and
discard "O" rings.
2) Disconnect condenser-to-evaporator line clip on right side
body rail, behind engine mount. Remove orifice tube using Orifice Tube
Remover/Installer (J-26549-E) or needle-nose pliers.
3) If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible. Using
a heat gun, carefully apply heat 1/4" from dimples on condenser inlet
line. Be careful not to overheat line.
4) If A/C pressure switch is located near orifice tube,
remove switch to protect it from heat. While heat is being applied,
grip orifice tube using orifice tube remover/installer or needle-nose
pliers. Use a turning motion along with a push-pull motion to loosen
and remove orifice tube.
Installation
1) Coat inside of condenser inlet line and "O" rings with
refrigerant oil. Lubricate orifice tube "O" ring with refrigerant oil
and insert into condenser inlet line. Insert orifice tube into
condenser inlet line with shorter screen toward evaporator.
2) Connect condenser-to-evaporator line clip on right side
body rail. Lubricate "O" rings and connect condenser inlet line.
Tighten condenser inlet line nut to 12 ft. lbs. (16 N.m). Install
closeout panel. Evacuate, charge, and test system for proper
operation.
Removal ("W" Body)
1) Locate orifice tube. See ORIFICE TUBE LOCATION &
REMOVER/INSTALLER APPLICATION table. Remove air cleaner and duct
assembly. Discharge A/C system, using approved recovery/recycling
equipment. Disconnect negative battery cable. Disconnect ABS modulator
and A/C pressure sensor/fan switch electrical connectors.

2) Disconnect liquid line/suction line bracket. Disconnect
liquid line at orifice tube. Remove orifice tube using specified
orifice tube remover/installer. See ORIFICE TUBE LOCATION &
REMOVER/INSTALLER APPLICATION table.
3) If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible. Using
a heat gun, carefully heat inlet line. If inlet line has small
dimples, apply heat 1/4" from dimples. Be careful not to overheat
line.
4) If A/C pressure switch is located near orifice tube,
remove switch to protect it from heat. While heat is being applied,
grip orifice tube using needle-nose pliers. Use a turning motion along
with a push-pull motion to loosen and remove orifice tube.
Installation
1) Coat inside of inlet line and "O" ring with refrigerant
oil. Lubricate orifice tube and "O" ring with refrigerant oil and
insert them into inlet line. Insert orifice tube into evaporator inlet
line with short screen toward condenser.
2) Tighten liquid line fitting at orifice tube to 20 ft. lbs.
(27 N.m). To complete installation, reverse removal procedure.
Evacuate, charge, and test system for proper operation.
Removal ("C" & "K" Series)
1) Discharge A/C system, using approved recovery/recycling
equipment. On models equipped with front A/C system only, remove front
grille. Using a backup wrench, loosen condenser-to-evaporator (liquid)\
line fitting at condenser and disconnect line.
2) On models equipped with rear A/C system, loosen condenser-
to-evaporator (liquid) line fitting between junction block and
evaporator. If necessary, remove air cleaner assembly.
3) On all models, remove and discard fitting "O" ring. Using
Orifice Tube Remover/Installer (J-26549-E), remove orifice tube from
liquid line. If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible.
4) Using a heat gun, carefully apply heat 1/4" from dimples
on liquid line. Be careful not to overheat line. If A/C pressure
switch is located near orifice tube, remove switch to protect it from
heat.
5) While heat is being applied, grip orifice tube using
orifice tube remover/installer. Use a turning motion along with a
push-pull motion to loosen and remove orifice tube.
Installation
1) Clean liquid line fitting with refrigerant oil. Coat
inside of liquid line and "O" ring with refrigerant oil. Lubricate
orifice tube and "O" ring with refrigerant oil and insert them into
liquid line. Insert longer orifice tube screen (inlet end) into
condenser outlet line first, toward condenser.
2) Tighten liquid line fitting to 18 ft. lbs. (24 N.m). To
complete installation, reverse removal procedure. Evacuate, charge,
and test system for proper operation.
Removal ("G", "L" & "M" Series)
1) Discharge A/C system, using approved recovery/recycling
equipment. Using a backup wrench, loosen evaporator inlet (liquid)
line fitting at evaporator. Disconnect inlet line. Remove and discard
"O" ring(s). Using Orifice Tube Remover/Installer (J-26549-E), remov\
e
orifice tube from liquid line.
2) If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible. Using
a heat gun, carefully apply heat 1/4" from dimples on liquid line. Be
careful not to overheat line.

3) If A/C pressure switch is located near orifice tube,
remove switch to protect it from heat. While heat is being applied,
grip orifice tube using orifice tube remover/installer. Use a turning
motion along with a push-pull motion to loosen and remove orifice
tube.
Installation
1) Clean liquid line fitting with refrigerant oil. Add one
ounce of refrigerant oil to system. Coat inside of liquid line and "O"
rings with refrigerant oil. Lubricate orifice tube and "O" ring with
refrigerant oil and insert them into liquid line. Insert shorter
orifice tube screen into liquid line first with long screen (inlet
end) toward condenser.
2) Tighten liquid line fitting to 20 ft. lbs. (27 N.m). To
complete installation, reverse removal procedure. Evacuate, charge,
and test system for proper operation.
Removal ("U" Series)
1) Remove air cleaner and duct assembly. Discharge A/C
system, using approved recovery/recycling equipment. Using a backup
wrench, loosen condenser outlet (liquid) line fitting at orifice tube.\
Disconnect liquid line. Remove and discard "O" rings. Using needle-
nose pliers, remove orifice tube from liquid line.
2) If difficulty is encountered during removal of a plugged
or restricted orifice tube, remove as much residue as possible. Using
a heat gun, carefully apply heat 1/4" from dimples on liquid line. Be
careful not to overheat line.
3) If A/C pressure switch is located near orifice tube,
remove switch to protect it from heat. While heat is being applied,
grip orifice tube using needle-nose pliers. Use a turning motion along
with a push-pull motion to loosen and remove orifice tube.
Installation
1) Clean liquid line fitting with refrigerant oil. Add one
ounce of refrigerant oil to system. Coat inside of liquid line and "O"
rings with refrigerant oil. Lubricate orifice tube and "O" ring with
refrigerant oil and insert them into liquid line. Insert orifice tube
into liquid line with long screen (inlet end) toward condenser.
2) Tighten liquid line fitting to 20 ft. lbs. (27 N.m). To
complete installation, reverse removal procedure. Evacuate, charge,
and test system for proper operation.
ORIFICE TUBE LOCATION & REMOVER/INSTALLER APPLICATION









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Application Orifice Tube Orifice Tube
Location Remover/Installer
Cars
"C" Body ...................... ( 1) .................. J-26549-D
"E" & "K" Body ................ ( 1) .................. J-26549-D
"F" Body .............. Evaporator Inlet .. ....................
"G" Body .............. Evaporator Inlet ............. J-26549-E
"H" Body .............. Condenser Outlet ............. J-26549-D
"J" Body .............. Condenser Outlet ............. J-26549-E
"N" Body ( 2) .......... Condenser Outlet ............. J-26549-E
"W" Body ...................... ( 3) .................. J-26549-E
Trucks & Vans
"C" & "K" Series
With Rear A/C ........ Evaporator Inlet ............. J-26549-E
Without Rear A/C ..... Condenser Outlet ............. J-26549-E
"G" Series ............ Evaporator Inlet ............. J-26549-E
"L" & "M" Series ...... Evaporator Inlet ............. J-26549-E
"S" & "T" Series ...... Evaporator Inlet ............. J-26549-D

4) Scan tool will automatically calculate system charge.
Depending on system charge condition, corrections are made 2 ounces at
a time. Each time a correction is made, recheck readings to ensure
proper charge. For system refrigerant capacity, see REFRIGERANT OIL &
REFRIGERANT SPECIFICATIONS article.
Breeze, Cirrus, Concorde, Intrepid, LHS, Stratus & 300M
(Manifold Gauge Set Method)
1) Attach clamp-on Thermocouple (80PK-1A) to liquid line, as\
close to condenser outlet as possible. Attach manifold gauge set to
vehicle.
2) Set parking brake, and place transaxle in Park position.
Start engine and allow to idle. Set A/C controls to outside air, panel
mode, full cool, and high blower speed. Turn A/C on, and open windows.
Operate system for a few minutes to allow system to stabilize.
3) Place cardboard over front grille area, to block airflow
through part of condenser, to set A/C pressure to 260 psi (18.3
kg/cm
). This will stop cooling fans from alternating speeds and
maintain constant pressure.
4) Record temperature reading at liquid line and discharge
pressure reading on gauges. Compare readings with values in
REFRIGERANT CHARGE LEVEL table.
5) Depending on system charge condition, corrections are made
2 ounces at a time. Each time a correction is made, recheck readings
to ensure proper charge. For system refrigerant capacity, see
REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article.
REFRIGERANT CHARGE LEVEL









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Liquid Line Temp. ( 1) Discharge PressureF (C) psi (kg/cm)
40 (4.4) ........................................... 53-75 (3.7-5.3\
)
60 (15.6) ......................................... 81-104 (5.7-7.3\
)
80 (26.7) ....................................... 111-142 (7.8-10.0\
)
100 (37.8) ..................................... 156-194 (11.0-13.6\
)
120 (48.9) ..................................... 208-259 (14.6-18.2\
)
140 (60.0) ..................................... 272-331 (19.1-23.3\
)
160 (71.1) ..................................... 353-420 (24.8-29.5\
)
180 (82.2) ..................................... 447-516 (31.4-36.3\
)
( 1) - When pressure is lower than specified, system is undercharged.
When pressure is higher than specified, system is overcharged.









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All Other Models
Ensure A/C system has been checked for leaks and evacuated.
See EVACUATING A/C SYSTEM and LEAK TESTING. Charge A/C system to
specifications. For system refrigerant capacity, see REFRIGERANT OIL &
REFRIGERANT SPECIFICATIONS article.
FORD MOTOR CO.
1) If using approved Recovery/Recycling/Charging Center (023-\
00105 or 023-00150), connect to high-side and low-side service valves.
See SERVICE VALVE LOCATIONS under SYSTEM SERVICE VALVES. Operate
charging center according to manufacturer's instructions. Charge
system with specified amount of refrigerant and refrigerant oil. See
REFRIGERANT OIL & REFRIGERANT SPECIFICATIONS article. Check amount of
refrigerant oil in system before adding oil. See COMPRESSOR
REFRIGERANT OIL CHECKING article.
2) If using manifold gauge set, connect to high-side and low-
side service valves. See SERVICE VALVE LOCATIONS under SYSTEM SERVICE

Fig. 24: Electronic Leak Detector
PREPARATION FOR LEAK TESTING
Connect manifold gauge set to air conditioning system. Ensure
low-side and high-side gauge set valves are closed. Check system
pressure. It should be at least 50 psi (3.5 kg/cm
). If system is
empty, evacuate A/C system and apply 28 in. Hg of vacuum. If system
holds vacuum for 15 minutes there most likely are no leaks present. If
low, add just enough refrigerant (about 10 ounces) to bring system to
50 psi (3.5 kg/cm
).
Ensure all joints, connections, and fittings are free of oil
dirt and other contaminants. Using a refrigerant leak detector, check
all refrigerant line connections for leaks. Check condenser and
compressor seal area.
Start engine and allow to idle. Operate A/C system for about
5 minutes. Set A/C controls to outside air, and high blower speed.
Turn A/C on, and open vehicle windows. Turn engine off and wait 2-7
minutes. Refrigerant is heavier than air. Always check for leaks at
bottom of refrigerant lines and components. Refrigerant oil will leak
with refrigerant. Visually check all connections and compressor clutch
area for oil stains. If compressor shaft seal is leaking, a fresh oil
streak will normally be seen on underside of hood, above compressor
clutch.
Always perform leak testing after A/C service. Move
refrigerant leak detector slowly to check for leaks, as leaks will not