Ac control DODGE RAM 2001 Service Owner's Manual

STABILIZER BAR
DESCRIPTION
The stabilizer bar extends across the underside of
the vehicle and is bolted to the axle. Links at the end
of the bar are bolted to the frame.
OPERATION
The stabilizer bar is used to minimize vehicle body
roll. The spring steel bar helps to control the vehicle
body in relationship to the suspension.
REMOVAL
(1) Raise and support vehicle.
(2) Remove nuts from the links at the stabilizer
bar and separate the links with Puller C-3894-A (Fig.
5) .
(3) Remove stabilizer bar retainer nuts and retain-
ers (Fig. 6) .
(4) Remove stabilizer bar and replace worn,
cracked or distorted bushings.
(5) Remove links upper mounting nuts and bolts
and remove links.
INSTALLATION
(1) Install link into frame brackets and install
mounting nuts and bolts.
(2) Install the stabilizer bar and center it with
equal spacing on both sides. Install stabilizer bar
retainers and tighten nuts to 54 N´m (40 ft. lbs.).
(3) Install stabilizer link ball studs into the bar
and tighten nuts to 68 N´m (50 ft. lbs.).
(4) Remove support and lower vehicle.
(5) Tighten upper link mounting nuts to 68 N´m
(50 ft. lbs.).
Fig. 5 Stabilizer Link
1 - LINK
2 - PULLER
Fig. 6 Stabilizer Bar Mounting Bolts And
1 - STABILIZER BAR
2 - RETAINERS
2 - 30 REARBR/BE

(8) Insert axle shaft into the tube and engage
splined end of the shaft with the shift collar.
(9) Install vacuum shift motor housing.
AXLE SHAFT SEALS
REMOVAL
(1) Remove hub bearings and axle shafts.
(2) Remove axle shaft seal from the differential
housing with a long drift or punch.Be careful not
to damage housing.
(3) Clean the inside perimeter of the differential
housing with fine crocus cloth.
INSTALLATION
(1) Apply a light film of oil to the inside lip of the
new axle shaft seal.
(2) Install inner axle seal (Fig. 26).
(3) Install axle shafts and hub bearings.
AXLE VACUUM MOTOR
DESCRIPTION
The disconnect axle control system consists of:
²Shift motor.
²Indicator switch.
²Vacuum switch.
²Vacuum harness (Fig. 27).
Fig. 24 Bearing Installer
1 - SHIFT MOTOR HOUSING OPENING
2 - SPECIAL TOOL 5041-3
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL D-354-3
5 - BEARING
Fig. 25 Seal Installer
1 - SHIFT MOTOR HOUSING OPENING
2 - SEAL
3 - AXLE TUBE
4 - LOCATION FOR OPEN-END WRENCH
5 - SPECIAL TOOL 5041-2
6 - NUT
7 - SPECIAL TOOL 5041-3
8 - SPECIAL TOOL 8409
Fig. 26 Seal Installer
1 - DIFFERENTIAL HOUSING
2 - POSITION FOR OPEN-END WRENCH
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL C-3716-A
5 - SEAL
6 - SPECIAL TOOL 8409
BR/BEFRONT AXLE - 216FBI 3 - 29
AXLE SHAFTS - INTERMEDIATE (Continued)

OPERATION
The shift motor receives a vacuum signal from the
switch mounted on the transfer case when the vehi-
cle operator wants to switch from two wheel drive
mode to four wheel drive mode, or vice versa. When
this signal is received, the shift motor begins to move
the shift fork and collar within the axle housing. In
the four wheel drive mode, the shift collar connects
the axle intermediate shaft to the axle shaft to sup-
ply engine power to both front wheels. In two wheel
drive mode, the shift collar is disengaged from the
intermediate shaft and the intermediate shaft is
allowed to free-spin. When the two shafts are disen-
gaged, the load on the engine is reduced, thereby pro-
viding better fuel economy and road handling.
Fig. 27 Vacuum Control System
1 - CHECK VALVE
2 - CONTROL SWITCH ON TRANSFER CASE
3 - AIR VENT FILTER
4 - AXLE SHIFT MOTOR
5 - INDICATOR SWITCH
3 - 30 FRONT AXLE - 216FBIBR/BE
AXLE VACUUM MOTOR (Continued)

AXLE VACUUM MOTOR
DESCRIPTION
The disconnect axle control system consists of:
²Shift motor.
²Indicator switch.
²Vacuum switch.
²Vacuum harness (Fig. 27).
OPERATION
The shift motor receives a vacuum signal from the
switch mounted on the transfer case when the vehi-
cle operator wants to switch from two wheel drive
mode to four wheel drive mode, or vice versa. Whenthis signal is received, the shift motor begins to move
the shift fork and collar within the axle housing. In
the four wheel drive mode, the shift collar connects
the axle intermediate shaft to the axle shaft to sup-
ply engine power to both front wheels. In two wheel
drive mode, the shift collar is disengaged from the
intermediate shaft and the intermediate shaft is
allowed to free-spin. When the two shafts are disen-
gaged, the load on the engine is reduced, thereby pro-
viding better fuel economy and road handling.
Fig. 26 Seal Installation
1 - DIFFERENTIAL HOUSING
2 - POSITION FOR OPEN-END WRENCH
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL 8417
5 - SEAL
6 - SPECIAL TOOL 8411
Fig. 27 Vacuum Control System
1 - CHECK VALVE
2 - CONTROL SWITCH ON TRANSFER CASE
3 - AIR VENT FILTER
4 - AXLE SHIFT MOTOR
5 - INDICATOR SWITCH
3 - 62 FRONT AXLE - 248FBIBR/BE
AXLE SHAFT SEALS (Continued)

DESCRIPTION N´m Ft. Lbs. In. Lbs.
Park Brake Pedal
Assembly
Mounting Bolts/Nuts28 21 250
Hub/Bearing
LD 4x2 Spindle Nut251 185 Ð
Hub/Bearing
HD 4x2 Spindle Nut380 280 Ð
Hub/Bearing
4x4 Hub/Bearing Bolts170 125 Ð
SPECIAL TOOLS
BASE BRAKES
HYDRAULIC/MECHANICAL
DESCRIPTION
This vehicle is equipped with front disc brakes and
rear drum brakes also certain vehicles have four
wheel disc brakes. The front and rear disc brakes
consist of dual piston calipers and ventilated rotors.
The rear brakes are dual brake shoe, internal
expanding units with cast brake drums. The parking
brake mechanism is cable operated and connected to
the rear brake trailing shoes. Power brake assist is
standard equipment. A vacuum operated power brake
booster is used on gas engine vehicles. A hydraulic
booster is used on diesel engine vehicles.
Two antilock brake systems are used on this vehi-
cle. A rear wheel antilock (RWAL) brake system and
all-wheel antilock brake system (ABS). The RWAL
and ABS systems are designed to retard wheel
lockup while braking. Retarding wheel lockup is
accomplished by modulating fluid pressure to the
wheel brake units. Both systems are monitored by a
microprocessor which controls the operation of the
systems.
Installer, Brake Caliper Dust Boot C-4340
Installer, Brake Caliper Dust Boot C-3716-A
Handle C-4171
Cap, Master Cylinder Pressure Bleed 6921
5 - 4 BRAKESBR/BE
BRAKES - BASE (Continued)

tube can be used for emergency repair when factory
replacement parts are not readily available.
To make a ISO flare use an ISO flaring tool kit.
(1) Cut off damaged tube with Tubing Cutter.
(2) Remove any burrs from the inside of the tube.
(3) Install tube nut on the tube.
(4) Position the tube in the flaring tool flush with
the top of the tool bar (Fig. 3). Then tighten the tool
bar on the tube.
(5) Install the correct size adaptor on the flaring
tool yoke screw.
(6) Lubricate the adaptor.
(7) Align the adaptor and yoke screw over the tube
(Fig. 3).
(8) Turn the yoke screw in until the adaptor is
squarely seated on the tool bar.
COMBINATION VALVE
DESCRIPTION
The combination valve contains a pressure differ-
ential valve and switch, metering valve and a rear
brake proportioning valve on 1500 and early
2500/3500 models with rear drum brakes. The combi-
nation valve/rear brake proportioning valve are not
repairable and must be replaced as an assembly.The pressure differential switch is connected to the
brake warning lamp.
The metering valve on the 1500 and early
2500/3500 models with rear drum brakes is used to
balance brake action between the front disc and rear
drum brakes.
The proportioning valve on the 1500 and early
2500/3500 models with rear drum brakes is used to
balance front-rear brake action at high decelerations.
OPERATION
PRESSURE DIFFERENTIAL SWITCH
The switch is triggered by movement of the switch
valve. The purpose of the switch is to monitor fluid
pressure in the separate front/rear brake hydraulic
circuits.
A decrease or loss of fluid pressure in either
hydraulic circuit will cause the switch valve to shut-
tle forward or rearward in response to the pressure
differential. Movement of the switch valve will push
the switch plunger upward. This closes the switch
internal contacts completing the electrical circuit to
the warning lamp. The switch valve may remain in
an actuated position until repair restores system
pressures to normal levels.
METERING VALVE (1500 Model)(and early
2500/3500 models with rear drum brakes)
The valve holds-off the initial pressure to the front
disc brakes until the rear brake shoes retracting
springs are overcome. The valve is designed to main-
tain front brake fluid pressure at 241-517 kPa (35-75
psi) until the hold-off limit of 310-689 kPa (100 psi)
is reached. At this point, the metering valve opens
completely permitting full fluid apply pressure to the
front disc brakes. This reduces front brake lining
wear during low deceleration stops.
PROPORTIONING VALVE (1500 Model)(and early
2500/3500 models with rear drum brakes)
The valve allows normal fluid flow during moder-
ate braking. The valve only controls fluid flow during
high decelerations brake stops, when a percentage of
rear weight is transferred to the front wheels.
DIAGNOSIS AND TESTING - COMBINATION
VALVE
Pressure Differential Switch
(1) Have helper sit in drivers seat to apply brake
pedal and observe red brake warning light.
(2) Raise vehicle on hoist.
(3) Connect bleed hose to a rear wheel cylinder
and immerse hose end in container partially filled
with brake fluid.
Fig. 3 ISO Flaring
1 - ADAPTER
2 - LUBRICATE HERE
3 - PILOT
4 - FLUSH WITH BAR
5 - TUBING
6 - BAR ASSEMBLY
BR/BEBRAKES 5 - 9
BRAKE LINES (Continued)

OPERATION - 2500/3500 WITH REAR DISC
BRAKES
To apply the parking brake the pedal is depressed.
This creates tension in the cable which pulls forward
on the park brake lever. The lever pushes the park
brake shoes outward and into contact with the drum
section of the rotor. The contact of shoe to rotor parks
the vehicle.
A torsion locking mechanism is used to hold the
pedal in an applied position. Parking brake release is
accomplished by the hand release.
A parking brake switch is mounted on the parking
brake lever and is actuated by movement of the
lever. The switch, which is in circuit with the red
warning light in the dash, will illuminate the warn-
ing light whenever the parking brake is applied.
Parking brake adjustment is controlled by a cable
tensioner mechanism. The cable tensioner, once
adjusted at the factory, should not need further
adjustment under normal circumstances. Adjustment
may be required if a new tensioner, or cables are
installed, or disconnected.
OPERATION - (1500 models) (Early 2500/3500
models with rear drum brakes)
To apply the parking brakes, the pedal is
depressed. This pulls the rear brake shoe actuating
levers forward. As the actuating lever is pulled for-
ward, the parking brake strut or cam, exerts a linear
force against the primary brake shoe. This action
presses the primary shoe into contact with the drum.
Once the primary shoe contacts the drum, force is
exerted through the strut/cam. This force is trans-
ferred through the strut/cam to the secondary brake
shoe causing it to pivot into the drum as well.
A torsion locking mechanism is used to hold the
pedal in an applied position. Parking brake release is
accomplished by the hand release.
A parking brake switch is mounted on the parking
brake lever and is actuated by movement of the
lever. The switch, which is in circuit with the red
warning light in the dash, will illuminate the warn-
ing light whenever the parking brake is applied.
Parking brake adjustment is controlled by a cable
tensioner mechanism. The cable tensioner, once
adjusted at the factory, should not need further
adjustment under normal circumstances. Adjustment
may be required if a new tensioner, or cables are
installed, or disconnected.
PEDAL
REMOVAL
(1) Release the parking brake.
(2) Raise the vehicle.(3) Loosen the cable tensioner nut at the equalizer
to create slack in the front cable.
(4) Lower the vehicle.
(5) Remove the knee bolster, (Refer to 23 - BODY/
INSTRUMENT PANEL/STEERING COLUMN
OPENING COVER - REMOVAL).
(6) Disconnect the brake lamp wire from the
switch on the pedal assembly.
(7) Roll the carpet back, loosen the front cable
grommet from the floorpan and the cable retainer.
(8) Disengage the cable end connector (Fig. 65)
from the arm on the pedal assembly.
(9) Remove the bolts/nuts from the pedal assembly
and remove the assembly.
INSTALLATION
(1) Position the replacement pedal assembly on the
dash and cowl.
(2) Install the bolts/nuts and tighten to 28 N´m (21
ft. lbs.).
(3) Connect the front cable to the arm on the pedal
assembly.
(4) Tighten the front cable grommet to the floor-
pan and the cable retainer, roll the carpet back.
(5) Connect the wires to the brake lamp switch.
(6) Install the knee bolster, (Refer to 23 - BODY/
INSTRUMENT PANEL/STEERING COLUMN
OPENING COVER - INSTALLATION).
(7) Raise the vehicle.
(8) Adjust the parking brake cable tensioner.
Fig. 65 Parking Brake Pedal Assembly
1 - PARK BRAKE PEDAL
2 - FRONT CABLE
5 - 36 BRAKESBR/BE
PARKING BRAKE (Continued)

OPERATIONÐCOOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
An optional factory installed maximum duty cool-
ing package is available on most models. This pack-
age will provide additional cooling capacity for
vehicles used under extreme conditions such as
trailer towing in high ambient temperatures.
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED OR STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.²Increasing engine speed for more air flow is rec-
ommended.
TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
AIR CONDITIONING; ADD-ON OR AFTER MARKET:
A maximum cooling package should have been
ordered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system compo-
nents should be installed for model involved per
manufacturer's specifications.
RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, (Refer to 7 - COOLING - DIAGNOSIS AND
TESTING)
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.
²If an open or shorted condition has developed in
the relay circuit controlling the electric radiator fan,
a Diagnostic Trouble Code (DTC) can be set.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the PCM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
Fig. 4 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
7 - 4 COOLINGBR/BE
COOLING (Continued)

ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
DIAGNOSIS AND TESTINGÐCOOLING SYSTEM
LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
checked. If leaks are present, black light will cause
additive to glow a bright green color.
The black light can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 5).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove radiator pressure cap from filler
neck and check coolant level. Push down on cap to
disengage it from stop tabs. Wipe inside of filler neck
and examine lower inside sealing seat for nicks,
cracks, paint, dirt and solder residue. Inspect radia-
tor-to- reserve/overflow tank hose for internal
obstructions. Insert a wire through the hose to be
sure it is not obstructed.
Inspect cams on outside of filler neck. If cams are
damaged, seating of pressure cap valve and tester
seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck (Fig. 6).
Operate tester pump to apply 103.4 kPa (15 psi)
pressure to system. If hoses enlarge excessively or
bulges while testing, replace as necessary. Observe
gauge pointer and determine condition of cooling sys-
tem according to following criteria:
Holds Steady:If pointer remains steady for two
minutes, serious coolant leaks are not present in sys-
tem. However, there could be an internal leak that
does not appear with normal system test pressure. If
it is certain that coolant is being lost and leaks can-
not be detected, inspect for interior leakage or per-
form Internal Leakage Test.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect radiator,
Fig. 5 Leak Detection Using Black LightÐTypical
1 - TYPICAL BLACK LIGHT TOOL
Fig. 6 Pressure Testing Cooling SystemÐTypical
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER
BR/BECOOLING 7 - 5
COOLING (Continued)

DIAGNOSIS AND TESTING - COOLING SYSTEM
GAS ENGINE
COOLING SYSTEM DIAGNOSISÐGASOLINE ENGINE
CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE
GAUGE READS LOW1. Has a Diagnostic Trouble Code (DTC)
been set indicating a stuck open
thermostat?1. (Refer to 25 - EMISSIONS CONTROL -
DESCRIPTION) for On-Board Diagnostics
and DTC information. Replace thermostat
if necessary.
2. Is the temperature sending unit
connected?2. Check the temperature sensor
connector. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL) Repair connector if
necessary.
3. Is the temperature gauge operating
OK?3. Check gauge operation. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER/
ENGINE TEMPERATURE GAUGE -
DESCRIPTION) . Repair as necessary.
4. Coolant level low in cold ambient
temperatures accompanied with poor
heater performance.4. Check coolant level in the coolant
reserve/overflow tank and the radiator.
Inspect system for leaks. Repair leaks as
necessary. Refer to the Coolant section of
the manual text for WARNINGS and
CAUTIONS associated with removing the
radiator cap.
5. Improper operation of internal heater
doors or heater controls.5. Inspect heater and repair as necessary.
(Refer to 24 - HEATING & AIR
CONDITIONING - DIAGNOSIS AND
TESTING) for procedures.
TEMPERATURE
GAUGE READS HIGH
OR THE COOLANT
WARNING LAMP
ILLUMINATES.
COOLANT MAY OR
MAY NOT BE LOST OR
LEAKING FROM THE
COOLING SYSTEM1. Trailer is being towed, a steep hill is
being climbed, vehicle is operated in slow
moving traffic, or engine is being idled
with very high ambient (outside)
temperatures and the air conditioning is
on. Higher altitudes could aggravate
these conditions.1. This may be a temporary condition and
repair is not necessary. Turn off the air
conditioning and attempt to drive the
vehicle without any of the previous
conditions. Observe the temperature
gauge. The gauge should return to the
normal range. If the gauge does not
return to the normal range, determine the
cause for overheating and repair. Refer to
Possible Causes (2-20).
2. Is the temperature gauge reading
correctly?2. Check gauge. (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER -
SCHEMATIC - ELECTRICAL) . Repair as
necessary.
3. Is the temperature warning illuminating
unnecessarily?3. (Refer to 8 - ELECTRICAL/
INSTRUMENT CLUSTER - SCHEMATIC -
ELECTRICAL).
4. Coolant low in coolant reserve/overflow
tank and radiator?4. Check for coolant leaks and repair as
necessary. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
BR/BECOOLING 7 - 7
COOLING (Continued)