1999 DODGE RAM cooling

procedure.
NOTE: On Durango rear A/C-heater assembly, blower motor and fan are
serviced as an assembly.
Removal (Durango - Rear)
1) Disconnect negative battery cable. Remove headliner from
passenger compartment of vehicle. Remove sun visors and sun visor arm
supports.
2) Remove coat hooks, overhead assist handle and dome light.
If equipped, remove overhead console. Remove air outlet bezel from
rear A/C-assembly. Remove rear blower motor switch. Remove upper
liftgate opening trim. Disengage "A", "B", "C", and "D" pillar trim as
necessary to prevent trim panel interference.
3) Move second and third row seats to cargo position. Move
front seats to full recline position. Remove headliner fasteners.
Carefully bow headliner and remove through lift gate opening.
4) Disconnect "B" pillar drain hoses from "Y" fittings.
Remove lower A/C-heater assembly cover. Disconnect blower motor
harness connector. Remove blower motor and fan assembly. To install,
reverse removal procedure.
Removal (Ram Pickup - Front)
1) Disconnect negative battery cable. Disconnect blower motor
cooling tube. Remove blower motor electrical connector from retainer.
Disconnect electrical connector. See Fig. 5.
2) Remove blower motor and fan assembly mounting screws.
Remove blower motor and fan assembly. Place reference marks on blower
motor and fan for reassembly reference. Remove blower motor fan
retainer clip. Pull blower motor fan off blower motor shaft.
Installation
Align reference marks made during removal. Press blower fan
hub onto blower motor shaft. Ensure retainer clip ears are indexed
over flats of blower motor shaft and fan hub. Ensure blower motor seal
is installed on housing. To complete installation, reverse removal
procedure.
BLOWER MOTOR RESISTOR
Removal & Installation (Dakota & Durango - Front)
Blower motor resistor is located in engine compartment, under
upper right corner of dash panel. Disconnect negative battery cable.
Remove cowl plenum cover to access resistor. Remove blower motor
resistor connector. Remove resistor retaining screws. Remove blower
motor resistor. To install, reverse removal procedure.
Removal & Installation (Durango - Rear)
1) Rear blower motor resistor is located in A/C-heater
assembly. Disconnect negative battery cable. Remove headliner from
passenger compartment of vehicle. Remove sun visors and sun visor arm
supports.
2) Remove coat hooks, overhead assist handle and dome light.
If equipped, remove overhead console. Remove air outlet bezel from
rear A/C-assembly. Remove rear blower motor switch. Remove upper
liftgate opening trim. Disengage "A", "B", "C", and "D" pillar trim as
necessary to prevent trim panel interference.
3) Move second and third row seats to cargo position. Move
front seats to full recline position. Remove headliner fasteners.
Carefully bow headliner and remove through lift gate opening.
4) Disconnect "B" pillar drain hoses from "Y" fittings.
Remove lower A/C-heater assembly cover. Disconnect rear blower motor
resistor connector. Remove screw and rear blower motor resistor. To

install, reverse removal procedure.
Removal & Installation (Ram Pickup - Front)
Blower motor resistor is located under glove box, attached to
blower motor housing. See Fig. 5. Disconnect negative battery cable.
Remove blower motor resistor connector. Remove resistor retaining
screws. Remove blower motor resistor. To install, reverse removal
procedure.
BLOWER MOTOR SWITCH (REAR)
Removal & Installation (Durango)
Disconnect negative battery cable. Pry above indentations at
outer perimeter of rear blower motor switch. Pull rear blower motor
switch and disconnect electrical connector. Remove rear blower motor
switch. To install, reverse removal procedure.
COMPRESSOR
Removal & Installation
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
refrigerant lines and plug or cover all openings in A/C system.
2) Remove drive belt. Disconnect compressor electrical leads.
Remove compressor mounting nuts and bolts. Remove compressor. Drain
oil from compressor, and record amount of oil drained.
3) To install, reverse removal procedure. Using new
refrigerant oil, add to compressor the same amount of oil drained from
it. Evacuate and charge A/C system.
CONDENSER
NOTE: Before removing condenser, note location of radiator and
condenser air seals. If air seals are not installed properly,
A/C and engine cooling systems will not perform properly.
Removal
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
A/C fittings at inlet and outlet of condenser. Plug or cover all
openings in A/C system.
2) On Dakota, remove bolts securing radiator and fan shroud
to inside of upper radiator crossmember. Remove top mounting bolts
securing condenser to upper crossmember. Tilt top of radiator and fan
shroud toward engine.
3) On Ram Pickup (gasoline engine), remove bolts securing
condenser upper mounting brackets to outside of upper radiator
crossmember. Tilt condenser away from engine compartment far enough to
grasp top of condenser with both hands. On Ram Pickup (diesel engine),\
remove bolts securing condenser to charge air cooler. On all models,
lift condenser assembly from vehicle.
Installation
To install, reverse removal procedure. Install new "O" rings
to fittings. Fill cooling system. Evacuate and charge A/C system.
EVAPORATOR CORE & HEATER CORE
Removal & Installation (Dakota & Durango - Front)
Remove instrument panel. See INSTRUMENT PANEL. Remove A/C-
heater assembly. See A/C-HEATER ASSEMBLY. With A/C-heater housing
removed, remove housing cover. Remove evaporator core or heater core

from housing. To install, reverse removal procedure. Install new "O"
rings to A/C fittings. Evacuate and charge A/C system.
Removal & Installation (Durango - Rear Evaporator Core)
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Remove
headliner from passenger compartment of vehicle. Remove sun visors and
sun visor arm supports.
2) Remove coat hooks, overhead assist handle and dome light.
If equipped, remove overhead console. Remove air outlet bezel from
rear A/C-heater assembly. Remove rear blower motor switch. Remove
upper liftgate opening trim. Disengage "A", "B", "C", and "D" pillar
trim as necessary to prevent trim panel interference.
3) Move second and third row seats to cargo position. Move
front seats to full recline position. Remove headliner fasteners.
Carefully bow headliner and remove through lift gate opening.
4) Disconnect "B" pillar drain hoses from "Y" fittings.
Disconnect "B" pillar refrigerant lines and plug or cover all openings
in A/C system. Remove lower A/C-heater assembly cover. Remove screws
securing refrigerant tube and retaining strap to right side of upper
housing cover. Remove evaporator core. To install, reverse removal
procedure. Install new "O" rings to A/C fittings. Evacuate and charge
A/C system.
Removal & Installation (Ram Pickup - Front)
1) Remove and disassemble A/C-heater housing. See
A/C-HEATER ASSEMBLY . Separate halves of A/C-heater housing and remove
top half. Remove evaporator or heater core from housing.
2) To install, reverse removal procedure. Install new "O"
rings to A/C fittings. Evacuate and charge A/C system. Fill cooling
system. On 5.9L diesel engine, engine is equipped with a one-way check
valve. DO NOT run engine while filling cooling system. Fill engine
with engine turned off.
INSTRUMENT PANEL
Removal & Installation (Dakota & Durango)
1) Disconnect negative battery cable. Disable air bag system.
See AIR BAG SYSTEM SAFETY article. Place front wheels in straight-
ahead position. Remove sill trim from both doorways. Remove kick panel
covers from both sides of vehicle. Remove mounting screws for hood
release handle.
2) Remove steering column trim panel and support bracket.
Remove tilt steering column lever (if equipped). Remove upper and
lower shrouds from steering column. Unplug driver's side air bag
module. Loosen multifunction switch wiring harness connector screw and
disconnect from switch. Screw will remain in connector.
3) Disconnect PRNDL cable. Disconnect shift cable from
steering column. Remove steering coupler lock pin. Remove toe plate
retaining screws. Remove steering column mounting bolts and remove
steering column from vehicle.
4) Remove screw from bulkhead wiring harness connector and
disconnect. Disconnect 2 body wiring harness connectors located next
to bulkhead connector. Disconnect 3 wiring harness connectors, from
junction block, located nearest to dash panel. Disconnect brake light
switch connector. Disconnect Rear Wheel Anti-Lock (RWAL) brake module
(if equipped), located near steering column support brackets.
5) Disconnect plastic retainer clip from parking brake
linkage rod, located at back of parking brake release handle. Remove
rod end from parking brake handle. Remove instrument panel center
support bracket. Unplug vacuum harness connector located at left end
of A/C-heater housing. Disconnect Air Bag Control Module (ACM)
connector.

6) Remove glove box. Reach through glove box opening and
disconnect antenna coaxial cable connector. Disconnect blower motor
connector located above glove box opening, near support brace for A/C-
heater housing. Disconnect radio ground strap. Loosen instrument panel
roll down bracket bolts about 2 turns, located at lower corners on
both sides of instrument panel. Remove 5 screws across top of dash
panel at base of windshield, removing center screw last.
7) Roll down instrument panel and install a temporary support
hook that is about 18" (457 mm) in length. Install hook from center
hole in instrument panel to center hole of dash panel. Pull lower
instrument panel outward until both roll down bracket bolts are in
slotted roll down position. Instrument panel should now be supported
and away from firewall.
8) Disconnect 2 door harness connectors, located on a bracket
near right end of instrument panel. Disconnect blower motor resistor.
Disconnect temperature control cable from A/C-heater housing and
remove from housing. See Fig. 5. Disconnect demister duct flexible
hose from A/C-heater housing.
9) Ensure instrument panel is free and clear for removal.
With the aid of an assistant, remove temporary support hook. Lift
instrument panel off of roll down bracket bolts and remove from
vehicle.
10) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.
Removal & Installation (Ram Pickup)
1) Disable air bag system. See AIR BAG SYSTEM SAFETY article.
Disconnect negative battery cable. Drain cooling system. Remove left
and right kick panel trim. Remove 5 screws and knee bolster/steering
column cover. Remove hood release and parking brake release handle
screws from lower instrument panel support. Remove 6 screws and
instrument panel support. Disconnect air bag connector at lower left
corner of instrument panel.
2) Pull PRNDL cable and twist to remove from position arm.
Push tab on bottom of cable retainer upward, then squeeze sides to
remove retainer from column. Remove tilt lever (tilt column only).
Remove both upper and lower shrouds from column. Remove lower fixed
column shroud. Loosen multifunction switch connector screw. Screw will
remain in connector.
3) Remove remaining steering column electrical connectors.
Remove air bag wiring harness from steering column wiring trough.
Remove wiring trough from steering column. Remove 3 toe plate nuts and
washers.
4) Remove 2 nuts and washers attaching steering column
bracket to instrument panel steering column support bracket. Allow
column to lower and rest on seat. Remove 2 screws from bottom of Air
Bag Control Module (ACM) cover. Remove 4 screws holding ACM to
transmission tunnel.
5) Disconnect wiring at ACM. Disconnect instrument panel left
side wiring connectors. Remove screw holding brake release to bottom
of instrument panel. Disconnect instrument panel right side wiring
connectors, which includes 2 connectors attached to A/C-heater
assembly housing, courtesy light connector, antenna cable and 2 body
connectors. Disconnect vacuum harness from A/C-heater system.
6) Remove 5 screws holding instrument panel to dash. Loosen
lower instrument panel pivot bolts. Roll instrument panel downward.
Remove instrument panel from vehicle.
7) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.

2) Ensure service hoses are equipped with valve core
depressor to match Schrader valve. If not, install special adapters
for this purpose. If the high-side service hose connector will not fit
on high-side Schrader valve, a special adapter must be used. See
SPECIAL VALVE CONNECTORS.
3) Ensure both manifold gauge set hand valves are closed.
Connect low-side service hose to low-side (suction) service valve, and\
finger tighten connections. Connect high-side service hose to high-
side (discharge) service valve, and finger-tighten connections.
NOTE: After test gauges are installed, test hoses must be purged of
all air before proceeding with testing.
PURGING TEST HOSES
1) Ensure high-side and low-side hoses are properly connected
to service valves, and all hose connections are tight. Place a clean
shop towel over end of center service hose.
2) Purge high-side test hose by opening hand valve on high-
side gauge for 3-5 seconds. This allows the system's refrigerant to
force air through test hoses and out of center service hose into the
shop towel. Immediately close high-side gauge hand valve.
3) Purge low-side test hose in the same manner using hand
valve of low-side gauge. Close hand valve after 3-5 seconds. Purging
of test hoses is now complete, and system is ready for testing.
NOTE: If manifold gauge set is to be used in conjunction with
refrigerant recovery/recycling equipment, use instructions
provided with the recovery/recycling equipment to properly
purge test hoses.
STABILIZING A/C SYSTEM
1) Once manifold gauge set is attached to system and test
hoses have been purged, the system is ready for testing. Place all
test hoses, gauge set and other equipment away from all moving parts
of engine.
2) Start engine, and turn A/C controls to maximum cooling
position (full cold or MAX A/C). Set blower on high speed. Open doors
and/or windows. Operate system for 5-10 minutes. System should now be
stabilized and ready for test readings.
PRESSURE-TEMPERATURE RELATIONSHIP
A refrigerant, when confined in an enclosed space, increases
in pressure as the temperature increases. Conversely, if the
temperature is lowered, the pressure also decreases.
Depending on temperature, a corresponding pressure will exist
in such an enclosed space. For example, at 70
F (21.1C) a gauge will
indicate about 71.0 psi (5.0 kg/cm). The R-134a PRESSURE- TEMPERATURE
RELATIONSHIP table shows this relationship.
R-134a PRESSURE-TEMPERATURE RELATIONSHIP









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Temperature F (C) ( 1) psi (kg/cm)
20 (-6.7) ................................................. 18 (1.3\
)
30 (-1.1) ................................................. 26 (1.8\
)
40 (4.4) .................................................. 35 (2.5\
)
50 (10.0) ................................................. 45 (3.2\
)
60 (15.6) ................................................. 57 (4.0\
)

Fig. 14: Insufficient Cooling Of Condenser Or R-134a Refrigerant
Overcharge

1) Manufacturer recommends flushing contaminated system using
one gallon of Ford A/C System Flushing Solvent (F4AZ-19579-A), a
Filter (FL-1A), an A/C Flusher Fitting Kit (014-00992). DO NOT reuse\
flushing solvent and filter, they are intended to be used on one
vehicle only.
2) Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Flush specified A/C components using A/C
System Flusher (014-00991), according to manufacturer's operating
instructions.
3) If an A/C system flusher is not available to clean A/C
system, an in-line filter kit can be used. Filter kit is installed
before replacement compressor, accumulator/receiver-drier, muffler,
and thermal expansion valve/fixed orifice tube have been installed.
4) Filter kits are used with either a rubber lined suction
hose or with a nylon lined suction hose located between compressor and
evaporator. Rubber lined hose has a wall thickness of 1/4" and nylon
lined hose has a wall thickness of 1/8". See Fig. 22.
5) The filter kit for either type hose has 2 filters. A
temporary pancake filter and a permanent in-line suction filter.
Pancake filter is temporarily installed between condenser and
condenser-to-evaporator line. See Fig. 23. Permanent filter is
installed in suction line between accumulator and compressor.
6) Install replacement components (compressor, accumulator
and fixed orifice) with correct amount of refrigerant oil. See
COMPRESSOR REFRIGERANT OIL CHECKING article.
7) Cut suction hose between compressor and accumulator
(closer to compressor). Remove a length of suction hose to accommodate\
suction filter. Measure side wall of suction hose and install
appropriate filter with "O" rings and filter clamps. If side wall is
1/4", use in-line filter labeled USE WITH RUBBER INNER LINED HOSE. If
side wall is 1/8", use in-line filter labeled USE WITH NYLON INNER
LINED HOSE. Ensure arrow on filter is pointing in direction of
refrigerant flow. Tighten hose clamps to 54 INCH lbs. (6 N.m). See
Fig. 22 .
8) Install pancake filter in liquid line between condenser
and condenser-to-evaporator line. Ensure filter inlet (label) is
toward condenser. Evacuate, charge, and leak test A/C system. See
EVACUATING A/C SYSTEM, CHARGING A/C SYSTEM and LEAK TESTING. Check
filters and hoses for clearance from other engine components. Use tie
straps if necessary.
9) Place an external cooling fan in front of radiator. Select
MAX A/C operation and set blower motor speed to maximum. Start engine
and allow to idle. Ensure A/C is operating properly. Slowly increase
engine speed to 800 RPM, then 1000 RPM, and then to 1200 RPM. With
engine speed set to 1200 RPM, operate engine for one hour with A/C
system operating.
10) Stop engine. Discharge A/C system, using approved
refrigerant recovery/recycling equipment. Remove pancake filter, hoses
and fittings. Discard pancake filter. Reconnect liquid line, evacuate,
charge, and leak test A/C system. Ensure A/C system is operating
properly.