1999 DODGE RAM belt


A/C -H EA TE R S YSTE M

1999 D odge P ic ku p R 1500
1999 MANUAL A/C-HEATER SYSTEMS
CHRYSLER
Dakota, Durango & Ram Pickup
SPECIFICATIONS
SPECIFICATIONS








\









\









\









\









\









\









\







Application Specification
Compressor Type .............................. Sanden SD-7H15 7-Cyl.
Compressor Belt Tension ........................................ ( 1)
Refrigerant (R-134a) Capacity
With Rear A/C Unit ....................................... 30 ozs.
Without Rear A/C Unit .................................... 28 ozs.
System Oil Capacity
Dakota & Ram Pickup ................................. ( 2) 8.1 ozs.
Durango
With Rear A/C Unit ................................. ( 2) 8.0 ozs.
Without Rear A/C Unit .............................. ( 2) 5.5 ozs.
System Operating Pressures ( 3)
High Side ......................... 190-220 psi (13.4-15.5 kg/cm
)
Low Side .............................. 32-40 psi (2.2-2.8 kg/cm)
( 1) - Dynamic tensioner automatically adjusts belt. Tension is okay if
indicator is within marked limits on belt tensioner.
( 2) - Use SP-20 PAG refrigerant oil.
( 3) - Measured at ambient air temperature of 80
F (27C).








\









\









\









\









\









\









\







WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all SERVICE PRECAUTIONS and DISABLING &
ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY
article.
CAUTION: When battery is disconnected, radio will go into anti-theft
protection mode. Obtain radio anti-theft protection code from
owner prior to servicing vehicle.
DESCRIPTION
These systems are a blend-air type. Outside air enters
through a cowl at base of the windshield and flows through a plenum
chamber into blower housing. Airflow velocity is controlled by blower
speed selector switch. Air flows across evaporator and is directed by
a blend-air door to go either through or by-pass the heater core.
On Dakota and Durango, temperature control cable operates
blend-air door and allows immediate control of outlet air temperature.
It also controls operation of recirculation door. On Ram Pickup,
temperature is regulated by a blend-air servo motor controlled from
A/C-heater control panel rotary temperature dial. On all models, mode
selector switch controls vacuum-operated doors to direct conditioned
air to selected outlets.
Durango may also be equipped with an optional rear A/C unit.
The rear A/C unit consists of a blower motor and evaporator. It will
only operate while the front A/C is on. The optional rear A/C-heater
unit is controlled using fan and temperature switches.

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

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.

AIR B AG R ESTR AIN T S YSTE M
1999 D odge P ic ku p R 1500
1999 AIR BAG RESTRAINT SYSTEMS
DaimlerChrysler Corp.
Dodge: Ram Pickup
DESCRIPTION & OPERATION
* PLEASE READ THIS FIRST *
WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all WARNINGS and SERVICE PRECAUTIONS.
Supplemental Restraint System (SRS) is designed to work in
conjunction with seat belts. SRS helps to reduce the risk or severity
of serious injury during a front-end collision. Driver-side air bag is
stored in a module in steering wheel hub. All models are equipped with
passenger-side air bags. Passenger-side air bag is stored in the
instrument panel, above glove box. All air bags are covered by a pad
bearing the air bag SRS logo.
Air bag(s) inflate and deflate within 1/10th of a second of
impact sensor switches closing. This creates a cushion of air between
driver and steering wheel and passenger and instrument panel.
System consists of an AIR BAG warning light, clockspring,
driver-side and passenger-side air bag modules, Air Bag Control Module
(ACM), one impact sensor (located inside ACM) and an energy reserve
capacitor. The ACM monitors system, stores fault codes (messages) and
provides information to AIR BAG warning light and Data Link Connector
(DLC). When a malfunction occurs, a fault code is stored and AIR BAG
warning light is activated for more than 12 seconds.
When impact sensor registers sufficient deceleration force
during a front-end collision, an electrical charge is sent from ACM to
air bag module inflator via the clockspring. Inflator actuates and
produces nitrogen gas, which inflates air bag(s).
AIR BAG WARNING LIGHT
Whenever ignition switch is in RUN or START position, AIR BAG
warning light on instrument panel will illuminate for 6-8 seconds and
then turn off. This signifies ACM has checked the system and found
that it is functioning properly. If AIR BAG warning light illuminates
for 12 seconds or more, stays on all the time or does not come on, a
system malfunction exists and trouble code will be stored.
IMPACT SENSOR
All models have one impact sensor located inside ACM. Impact
sensor is an accelerometer that measures deceleration. During a front-
end collision, a signal is sent that completes an electrical circuit
to inflators. Inflators actuate and produce nitrogen gas, which
inflates each air bag. Impact sensor is calibrated for a specific
vehicle and react to severity and direction of vehicle impact.
AIR BAG MODULE
WARNING: DO NOT attempt to disassemble air bag modules. Air bag
modules are not serviceable.
Driver-Side
Air bag module is mounted on front face of steering wheel. A

Fig. 8: Locating Seat Belt Control Timer Module & Main Seat Connector
Courtesy of DaimlerChrysler Corp.
Fig. 9: Identifying Seat Belt Control Timer Module (SCTM)
Connector Terminals
Courtesy of DaimlerChrysler Corp.

NOTE: All active codes must be resolved before diagnosing store
codes.
1) Raise and support vehicle. Start engine and let idle with
transmission in PARK position. Wiggle wiring harness and connectors of
air bag system and rotate steering wheel from stop to stop.
2) Visually inspect related wire harness connectors. Look for
broken, bent, pushed out, spread, corroded or contaminated terminals.
Also, look for chafed, pierced, pinched or partially broken wires.
3) Check for trouble codes as you work through system. If
stored trouble code becomes active, perform appropriate diagnostic
test. If stored code is reproducible, repair or replace wiring
harness, harness connector or terminals or replace component as
necessary.
CLUSTER MESSAGE MISMATCH
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect
it to ensure it is in good condition. Always focus on circuit
being tested. Dirt, water and corrosion, are most common
problems in connectors. Due to manufacturer changes in wire
colors, use terminal identification whenever possible.
1) If AIR BAG warning light is on, go to next step. If AIR
BAG warning light is not on, go to step 5).
2) Using DRB, select PASSIVE RESTRAINTS, AIRBAG and MONITOR
DISPLAY. Read WARNING LAMP STATUS. If DRB does not display MIC LAMP
STATUS ON, replace instrument cluster. If DRB displays MIC LAMP STATUS
ON, go to next step.
3) If DRB displays ACM LAMP REQUEST: ON, go to next step. If
DRB does not display ACM LAMP REQUEST: ON, replace instrument cluster.
4) If there are no potential causes for this DTC remaining,
ACM is assumed to be defective. Replace ACM. See
AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION.
NOTE: If AIR BAG warning light is defective, instrument cluster
will flash seat belt light for 30 seconds starting 10 seconds
after bulb check stops.
5) Using DRB, read air bag control module active codes
(messages). If CLUSTER MISMATCH is only active message, go to next
step. If other messages are present, go to appropriate diagnostic test
to continue diagnosis.
6) If seat belt warning light flashes for 30 seconds after
bulb check is complete, replace instrument cluster. If seat belt
warning light does not flashes for 30 seconds after bulb check is
complete, go to next step.
7) Using DRB, select PASSIVE RESTRAINTS, AIRBAG and MONITOR
DISPLAY. Read WARNING LAMP STATUS. If DRB displays ACM LAMP REQUEST:
OFF, go to next step. If DRB does not display ACM LAMP REQUEST: OFF,
replace instrument cluster.
8) If DRB displays MIC LAMP REQUEST: OFF, go to next step. If
DRB does not display MIC LAMP REQUEST: OFF, replace instrument
cluster.
9) If there are no potential causes for this DTC remaining,
ACM is assumed to be defective. Replace ACM. See
AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION.
DRIVER SQUIB CIRCUIT OPEN
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect

Reconnect battery. Using a voltmeter, check voltage between ground and
passenger-side air bag module 2-pin connector terminals "A" and "B".
If voltage is more than 0.5 volt on either circuit, go to next step.
If voltage is less than 0.5 volt on either circuit, replace ACM.
4) Disconnect PAD switch 4-pin connector. Using a voltmeter,
check voltage between ground and passenger-side air bag module 2-pin
connector terminals "A" (Black/Yellow wire) and "B" (Dark Green/Yello\
w
wire). If voltage is more than 0.5 volt in either circuit, repair
short in Black/Yellow wire or Dark Green/Yellow wire. If voltage is
less than 0.5 volt in either circuit, go to next step.
5) Using a voltmeter, check voltage between ground and PAD
switch 4-pin connector (harness side) terminals No. 1 (Brown/Yellow
wire) and No. 2 (Violet/Yellow wire). If voltage is more than 0.5 vol\
t
on either circuit, repair short in Brown/Yellow wire or Violet/Yellow
wire. If voltage is less than 0.5 volt on either circuit, replace PAD
switch.
REPAIRING SEAT BELT CONTROL TIMER MODULE (SCTM)
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect
it to ensure it is in good condition. Always focus on circuit
being tested. Dirt, water and corrosion, are most common
problems in connectors. Due to manufacturer changes in wire
colors, use terminal identification whenever possible.
1) Using a voltmeter, backprobe (do not disconnect connector)\
main seat connector terminal No. 10 (Light Green/Black wire) to
ground. See WIRING DIAGRAMS for terminal identification. If voltage is
between 1-3 volts, replace ACM. If voltage is less than one volt,
repair open in Light Green/Black wire. If voltage is between 9-10
volts, perform Seat Belt Control Timer Module (SCTM) diagnostics.
Repair as required. If voltage is not between 9-10 volts, go to next
step.
2) Disconnect SCTM connector. Using a voltmeter, check
voltage between ground and SCTM connector terminal No. 11 (Light
Green/Black wire). If voltage is between 9-10 volts, replace SCTM. If
voltage is not between 9-10 volts, go to next step.
3) Turn ignition off. Using an ohmmeter, check resistance
between ground and SCTM connector terminal No. 11 (Light Green/Black
wire). If resistance is less than 5 ohms, repair short in Light
Green/Black wire. If resistance is more than 5 ohms, go to next step.
4) Using an ohmmeter, check resistance between ground and
SCTM connector terminals No. 6 (Black/Light Green wire) and No. 13
(Black/Pink wire). If resistance is more than 5 ohms on either
circuit, repair open in Black/Light Green wire or Black/Pink wire. If
resistance is less than 5 ohms on either circuit, go to next step.
5) Turn ignition off. Using a voltmeter, check voltage
between ground and SCTM connector terminal No. 4 (Dark Blue wire). If
voltage is less than 10 volts, repair open in Dark Blue wire. If
voltage is more than 10 volts, go to next step.
6) Using a voltmeter, check voltage between ground and SCTM
connector terminal No. 5 (Pink wire). If voltage is less than 10
volts, repair open in Pink wire. If voltage is more than 10 volts,
replace SCTM.
REPAIRING SCTM MESSAGE MISMATCH
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect
it to ensure it is in good condition. Always focus on circuit
being tested. Dirt, water and corrosion, are most common
problems in connectors. Due to manufacturer changes in wire

colors, use terminal identification whenever possible.
1) If seat belt light is on, go to step 4). If seat belt
light is not on, go to next step.
2) Using DRB, select PASSIVE RESTRAINTS, AIRBAG AND MONITOR
DISPLAY. Read WARNING LAMP STATUS. If DRB does not display MIC S/B
LAMP STATE: OFF, replace instrument cluster. If DRB displays MIC S/B
LAMP STATE: OFF, go to next step.
3) If DRB displays ACM S/B LAMP REQUEST: OFF, replace ACM. If
DRB does not display ACM S/B LAMP REQUEST: OFF, replace instrument
cluster.
4) Using DRB, select PASSIVE RESTRAINTS, AIRBAG AND MONITOR
DISPLAY. Read WARNING LAMP STATUS. If DRB does not display MIC S/B
LAMP STATE: ON, replace instrument cluster. If DRB displays MIC S/B
LAMP STATE: ON, go to next step.
5) Using DRB, read WARNING LAMP STATUS. If DRB does not
display ACM S/B LAMP REQUEST: ON, replace instrument cluster. If DRB
displays ACM S/B LAMP REQUEST: ON, replace ACM.
REPAIRING VIN MESSAGE MISMATCH
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect
it to ensure it is in good condition. Always focus on circuit
being tested. Dirt, water and corrosion, are most common
problems in connectors. Due to manufacturer changes in wire
colors, use terminal identification whenever possible.
1) Using DRB, select ENGINE (PCM). If DRB displays NO
RESPONSE FROM PCM, perform REPAIRING SHORT TO BATTERY under VEHICLE
COMMUNICATIONS. If DRB does not display NO RESPONSE FROM PCM, and
vehicle is a Club Cab (BE), go to next step. If DRB does not display
NO RESPONSE FROM PCM, and vehicle is a Standard Cab (BR), go to step
3).
2) Using DRB, select PASSIVE RESTRAINTS, AIRBAG AND MONITOR
DISPLAY. Select VIN type to identify 7th digit of VIN (VIN 2 or 3 is
for Club Cab; VIN B is for a Standard Cab). If DRB does not display
PCM VIN: BE, replace powertrain control module. If DRB displays PCM
VIN: BE, replace ACM.
3) Using DRB, select PASSIVE RESTRAINTS, AIRBAG AND MONITOR
DISPLAY. Select VIN type to identify 7th digit of VIN (VIN B is for a
Standard Cab). If DRB does not display PCM VIN: BE, replace powertrain
control module. If DRB displays PCM VIN: BE, replace ACM.
WARNING LAMP CIRCUIT OPEN/SHORTED
NOTE: Perform AIR BAG VERIFICATION TEST after
all repairs. Each time a connector is disconnected, inspect
it to ensure it is in good condition. Always focus on circuit
being tested. Dirt, water and corrosion, are most common
problems in connectors. Due to manufacturer changes in wire
colors, use terminal identification whenever possible.
1) Using DRB, select MECHANICAL INSTRUMENT CLUSTER (MIC). If\
DRB displays NO RESPONSE FROM MIC, go to
NO RESPONSE FROM INSTRUMENT CLUSTER under VEHICLE COMMUNICATIONS. If
DRB does not display NO RESPONSE FROM MIC, go to next step.
2) Using DRB, select PASSIVE RESTRAINTS AIRBAG AND MONITOR
DISPLAY. Read WARNING LAMP status. If DRB does not display MIC BULB
STATE, replace instrument cluster. If DRB displays MIC BULB STATE, go
to next step.
3) If DRB does not display MIC DRIVER STATE OK, replace
instrument cluster. If DRB displays MIC DRIVER STATE OK, go to next