DODGE RAM 1999 Service Repair Manual

data plate. See Fig. 3. There are 21 different calibrations available.
Repair as necessary.
Fig. 3: Identifying Pump Keyway & Pump Data Plate
Courtesy of Chrysler Corp.
3) Reinstall pump timing gear. Ensure timing marks on
crankshaft gear, camshaft gear and fuel pump gear are aligned. See

Fig. 4. Repair as necessary. After repairs are done, clear DTCs.
Fig. 4: Identifying Timing Gear Marks
Courtesy of Chrysler Corp.
IDLE SPEED
Idle speed is controlled by Engine Control Module (ECM). Idle\
speed is not adjustable.
THROTTLE POSITION SENSOR
THROTTLE POSITION SENSOR ADJUSTMENT
Throttle position sensor may also be referred to as
Acceleration Pedal Position Sensor (APPS). Throttle Position (TP)
sensor is not adjustable.










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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

protective cover is fitted to front of air bag module bearing the SRS
air bag logo. Air bag module contains air bag cushion, inflator and
supporting components. Air bag module is a sealed unit and is not
serviceable. The module inflator assembly produces nitrogen gas to
fill air bag cushion when a small amount of current from ACM is
applied to the ignitor assembly. Gas pressure builds and discharges
from inflator through a diffuser and screen assembly, forcing steering
wheel cover to burst along its seams until air bag is fully inflated.
Once air bag cushion is fully inflated, gas escapes from bag through
vents, away from driver.
Passenger-Side
Air bag module is mounted to instrument panel mounting
bracket. Module is covered by a protective door bearing the SRS air
bag logo. When supplied an electrical signal, inflator will discharge
argon gas directly into air bag. When air bag inflates, protective
door will pivot aside allowing air bag to deploy.
AIR BAG CONTROL MODULE (ACM)
ACM is located under instrument panel, on transmission
tunnel. Impact sensor, energy reserve capacitor and On-Board
Diagnostics (OBD) are an integral part of ACM. ACM monitors critical
input and output circuits within air bag system, ensuring they are
operating correctly. Some circuits are tested continuously; others are
checked only under certain conditions. ACM provides information about
air bag system through AIR BAG warning light and Data Link Connector
(DLC). When diagnostic trouble code (fault message) is stored, AIR B\
AG
warning light will be activated for 12 seconds or more.
DATA LINK CONNECTOR (DLC)
DLC is located under left side of instrument panel, left of
steering column. DLC is used to access SRS on-board diagnostics.
CLOCKSPRING
Clockspring connects air bag module to steering column
wiring, completing air bag system circuit. See Fig. 1. Inside
clockspring is a flat, ribbon-like tape of conductive material, which
winds and unwinds with steering wheel movement. Clockspring is the
most fragile part of air bag system. Clockspring must be centered
properly to allow 1 1/2 steering wheel turns in either direction. If
clockspring is not centered properly, it can break from stretching or
fatigue.
Fig. 1: Identifying Clockspring Assembly
Courtesy of DaimlerChrysler Corp.

PASSENGER AIR BAG DISARM (PAD) SWITCH
PAD switch is mounted on instrument panel. Switch allows
passenger-side airbag module to be disarmed when rear facing child
safety seat is being used. PAD switch is operated with ignition key.
SYSTEM OPERATION CHECK
Turn ignition on and observe AIR BAG warning light. AIR BAG
warning light should illuminate for 6-8 seconds and then go out,
indicating system is functioning properly. If AIR BAG warning light
either fails to illuminate or illuminates continuously, a system
malfunction exists. Perform self-diagnostics. See DIAGNOSIS & TESTING.
After completing necessary repairs, turn ignition switch to
ON position. Ensure no one is inside vehicle, then connect negative
battery cable. Using DRB, erase stored Diagnostic Trouble Codes (DTC).\
See DIAGNOSIS & TESTING .
SERVICE PRECAUTIONS
These precautions should be observed when working with air
bag systems:
* Disable air bag system before servicing any air bag system
or steering column component. Failure to do this could
result in accidental air bag deployment and possible
personal injury. See DISABLING & ACTIVATING AIR BAG SYSTEM .
* Back-up power supply maintains deployment voltage for about
2 minutes after battery is disconnected. When disabling air
bag system, always wait at least 2 minutes after
disconnecting battery cables to resume procedure.
* After repairs, ensure AIR BAG warning light works
properly and no system faults are indicated. See
SYSTEM OPERATION CHECK .
* Always wear safety glasses when servicing or handling an
air bag.
* All SRS component fasteners are specially coated and are
designed with a specific function. Never replace SRS
component fasteners with other than original equipment parts.
* Air bag module must be stored in its original special
container until used for service. It must be stored in a
clean, dry, place, away from sources of extreme heat, sparks
and high electrical energy.
* When placing a live air bag on a bench or other surface,
always face air bag and trim cover up, away from surface.
This will reduce motion of module if accidentally deployed.
* After deployment, air bag surface may contain deposits of
sodium hydroxide, which irritates skin. Always wear safety
glasses, rubber gloves, and long-sleeved shirt during
clean-up and wash hands using mild soap and water. Follow
correct disposal procedures. See DISPOSAL PROCEDURES.
* Because of critical system operating requirements, DO NOT
attempt to service any air bag components. Corrections are
only made by replacing defective part.
* Electrical sources should never be allowed near inflator on
back of air bag module.
* When carrying a live air bag module, trim cover should be
pointed away from your body to minimize injury in case of
deployment.
* When testing voltage or continuity at Air Bag Control Module

(ACM), use wire side (not terminal end) of connector.
* DO NOT probe a wire through insulator, as this will damage
it and eventually cause failure.
* When performing electrical tests, prevent accidental
shorting of terminals. Such shorts can damage fuses or
components and may cause a second fault code to set, making
diagnosis of original problem more difficult.
* When diagnosing air bag system, use DRB volt/ohmmeter
unless instructed to use an external volt/ohmmeter. NEVER
use an analog volt/ohmmeter or test light in place of a
digital volt/ohmmeter.
* When using DRB to diagnose an air bag system problem,
operate DRB from outside of vehicle. DO NOT sit inside of
vehicle.
* Never use an ohmmeter to measure resistance of air bag
module. Accidental air bag deployment may occur, causing
personal injury.
* If air bag system is not fully functional for any reason,
vehicle should not be driven until system is repaired and
again becomes operational. DO NOT remove bulbs, modules,
sensors, or other components or in any way disable system
from operating normally. If air bag system is not
functional, park vehicle until it is repaired and functions
properly.
* When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may
exist until computer systems have completed a relearn cycle.
See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION
before disconnecting battery.
DISABLING & ACTIVATING AIR BAG SYSTEM
WARNING: Wait at least 2 minutes after disconnecting negative battery
cable before servicing air bag system. System reserve
capacitor, integral to ACM, maintains air bag system voltage
for about 2 minutes after battery is disconnected. Servicing
air bag system before 2-minute period may cause accidental
deployment of air bag(s) and possible personal injury. DO NOT\
use computer system memory saving devices. Enough voltage to
deploy air bag(s) may be provided from device.
CAUTION: When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may
exist until computer systems have completed a relearn cycle.
See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION
before disconnecting battery.
Disabling System
To disable air bag system for repairs, ensure ignition switch
is in OFF position. Disconnect and shield negative battery cable.
After disconnecting negative battery cable, wait at least 2 minutes
for reserve capacitor to discharge before servicing air bag system.
Activating System
Reconnect negative battery cable. From a position clear of air bag(s),\
turn ignition on. Perform system operation check. See
SYSTEM OPERATION CHECK .
DISPOSAL PROCEDURES
DEPLOYED AIR BAG CLEAN-UP

WARNING: Vehicle interior will contain sodium hydroxide powder, a
by-product of air bag deployment. Since this powder can
irritate skin, eyes, nose, or throat, be sure to wear
safety glasses, rubber gloves and long-sleeved shirt
during clean-up.
1) Begin clean-up by putting tape over air bag exhaust vent,
so no additional powder will escape into vehicle interior. Remove air
bag modules. Use a vacuum cleaner to remove any residual powder from
vehicle interior. To avoid kneeling or sitting on a non-cleaned area,
clean from outside vehicle and work your way inside.
2) Remove any residual powder from A/C-heater outlets. Turn
blower motor to low for a few minutes and exit vehicle. Turn blower
off. Vacuum any additional powder expelled from plenum. Vacuum
interior a second time to recover all powder.
DEPLOYED AIR BAG
Dispose of deployed air bag module as any other part. No
special disposal procedure is required.
UNDEPLOYED AIR BAG
NOTE: Information on passenger-side air bag deployment is not
available from manufacturer.
Procedure 1: In-Vehicle Deployment (Driver-Side Air Bag)
1) Use this procedure if scrapping a vehicle with an
undeployed air bag. This procedure assumes that air bag wiring is
intact.
2) Disconnect and shield negative battery cable. Disconnect
2-pin clockspring at base of steering column. Cut 2-pin clockspring
connector of at clockspring side of harness.
3) Strip 1" (25 mm) of insulation from wire ends. Make a
harness consisting of 2 wires 20 feet or longer. Connect 20-foot wires
to clockspring harness. Ensure there are no loose parts in passenger
compartment and no one is within 20 feet of vehicle.
4) Staying at least 20 feet away from vehicle, connect other
2 ends of 20 foot wires to terminals of a 12-volt battery. When
deployment is achieved, loud bang will be heard and air bag will
inflate. After air bag module deploys, let module cool and dust settle
before approaching. If air bag fails to deploy, go to PROCEDURE 2.
Procedure 2: Remote Deployment (Driver-Side Air Bag)
1) Use this procedure if scrapping a vehicle with a live air
bag, but a problem in electrical system prevent deployment with air
bag still installed in vehicle. Also use this procedure if PROCEDURE 1
was unsuccessful.
WARNING: Perform remote deployment outdoors. Never attempt to deploy
air bag module inside a building, within 20 feet of
personnel, or with air bag trim cover face down.
2) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM . Remove air bag
module. See DRIVER-SIDE AIR BAG MODULE under REMOVAL & INSTALLATION.
3) cut pigtail wiring harness between clockspring and air bag
as close to clockspring housing as possible. Reconnect other end of
pigtail harness back into air bag module.
4) Strip 1" (25 mm) of insulation from cut ends of harness.
Place air bag module face (trim cover) up. Connect two 20-foot wires
to end of harness wires. Move 20 feet away. Connect other end of 200-

foot wires to terminals of a 12-volt battery. After air bag module
deploys, let module cool off and allow dust to settle before
approaching.
POST-COLLISION INSPECTION
When a vehicle has been involved in a collision, certain
components of the passive restraint system must be inspected or
replaced. See PASSIVE RESTRAINT SYSTEM INSPECTION article in the
GENERAL INFORMATION section for post-collision inspection information.
REMOVAL & INSTALLATION
* PLEASE READ THIS FIRST *
WARNING: Failure to follow air bag service precautions may
result in air bag deployment and personal injury. See
SERVICE PRECAUTIONS . After component replacement,
ensure proper system operation. See SYSTEM OPERATION CHECK.
CAUTION: When battery is disconnected, vehicle computer and memory
systems may lose memory data. Driveability problems may
exist until computer systems have completed a relearn cycle.
See COMPUTER RELEARN PROCEDURES in GENERAL INFORMATION
before disconnecting battery.
AIR BAG CONTROL MODULE (ACM)
WARNING: ACM contains impact sensor, which enables SRS to activate air
bag. To avoid accidental air bag deployment, DO NOT connect
ACM electrically to system unless it is bolted to vehicle.
Removal
1) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM . Remove bottom
of center console (ACM trim cover).
2) On M/T models, remove center console from floor panel
transmission tunnel. On A/T models, remove screws securing trim cover
to ACM mounting bracket. See Fig. 2. Pull top of trim cover rearward
to release snap clips from instrument panel support bracket.
3) On all models, loosen but do not remove screws on sides
that secure instrument panel support bracket to ACM mounting bracket.
See Fig. 3 .
4) Remove nuts securing support bracket to studs on lower
instrument panel. Disconnect wire harness retainer from hole in
support bracket. Pull top of support bracket away from instrument
panel studs and fold down over ACM until it is laying on floor panel.
Unplug wire harness connector from ACM.
CAUTION: Always replace ACM and ACM mounting bracket as an assembly.
Replacement ACM includes a NEW mounting bracket. DO NOT mount
NEW ACM to old mounting bracket.
5) Remove screws securing mounting bracket to floor panel
transmission tunnel. Remove ACM, mounting bracket and support bracket
as a unit from floor panel.
Installation
To complete installation, reverse removal procedure. Install
ACM with arrow pointing toward front of vehicle. Connect ACM
connectors, ensuring connectors are locked into position. Tighten ACM

mounting screws and support bracket nuts to 125 INCH lbs. (14 N.m). DO\
NOT connect negative battery cable at this time. Go to
SYSTEM OPERATION CHECK.
Fig. 2: Identifying ACM Trim Cover (A/T Models)
Courtesy of DaimlerChrysler Corp.
Fig. 3: Removing Air Bag Control Module
Courtesy of DaimlerChrysler Corp.
DRIVER-SIDE AIR BAG MODULE

CAUTION: When removing a deployed air bag, wear eye protection, rubber
gloves and a long-sleeve shirt. Powder residue from air bag
deployment may irritate skin and eyes.
CAUTION: Before removing steering wheel, position front wheels in
straight-ahead position and lock steering column by removing
ignition key. Failure to do so could damage clockspring or
cause clockspring to be off-centered. DO NOT hammer on
steering wheel during removal, or collapsible column could be
damaged.
Removal
1) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM . Air bag module
is mounted on face of steering wheel. Ensure wheels are pointed
straight-ahead and steering wheel is locked.
2) Remove air bag module-to-steering wheel screws from back
side of steering wheel. Lift air bag module and disconnect electrical
connectors from rear of module.
Installation
Connect air bag, cruise control and horn harness connectors
to rear of air bag module. Secure module to steering wheel. Tighten
air bag module-to-steering wheel screws to specification. See
TORQUE SPECIFICATIONS . DO NOT connect negative battery cable at this
time. Go to SYSTEM OPERATION CHECK .
PASSENGER-SIDE AIR BAG MODULE
Removal
1) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) Open glove box. Holding glove box door, push center of
glove box bin towards front of vehicle. Flex glove box bin far enough
so glove box stops will clear sides of instrument panel opening. Roll
glove box down until stop bumpers are beyond sides of instrument panel
opening. Release bin. Lift bottom of glove box upward to disengage
hinge hooks form hinge pins.
3) Remove 3 screws securing instrument panel glove box
opening upper trim strip to instrument panel glove box opening upper
reinforcement, then remove trim strip. Remove 4 screws that secure 2
plastic support brackets of passenger-side air bag door panel outlet
housing to glove box opening upper reinforcement.
4) Reach through and above glove box opening to access and
disconnect air bag module harness connector. Remove 2 screws securing
passenger-side air bag module front bracket to instrument panel
structural support. Remove 3 screws securing passenger-side air bag
module rear bracket to glove box opening upper reinforcement.
5) Using trim stick, gently pry passenger-side air bag door
(starting at lower left edge) away from instrument panel top cover.
Remove air bag module, air bag door and panel outlet housing and
barrel assembly from instrument panel as a unit.
Installation
To install, reverse removal procedure. Ensure air bag door is
securely attached to instrument panel. Ensure air bag harness
connector latches fully engaged. DO NOT connect negative battery cable
at this time. Go to SYSTEM OPERATION CHECK .
CLOCKSPRING
CAUTION: Failure to position wheels in the straight-ahead position
with steering wheel locked when removing steering wheel could