1999 DODGE RAM instrument panel

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

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

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

damage clockspring and/or require clockspring to be
readjusted.
NOTE: Clockspring is self-centering and will automatically lock in
the centered position when steering wheel is removed.
Adjustment is only required if centering position is
disturbed.
Removal
1) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) Clockspring is located behind steering wheel. See Fig. 1.
Ensure front wheels are in straight-ahead position. Lock steering
wheel. Remove air bag module. See AIR BAG MODULE.
3) Remove steering wheel nut. Using appropriate steering
wheel puller, remove steering wheel. When steering wheel is removed,
self-centering clockspring will automatically lock in place. Remove
upper and lower steering column shrouds to gain access to clockspring
wiring.
4) Remove knee bolster (if equipped). Disconnect Yellow 2-wa\
y
clockspring harness connector between clockspring and instrument panel
wiring harness, at base of steering column. See Fig. 13. Remove
clockspring by releasing 2 tabs on side of clockspring. Clockspring
cannot be repaired and must be replaced if faulty.
Installation
1) Snap clockspring onto steering column. If clockspring
centering adjustment is disturbed, adjust clockspring before
installing steering wheel. See CLOCKSPRING CENTERING under
ADJUSTMENTS. Connect clockspring wiring connectors. Install steering
column covers. Install knee bolster (if removed).
2) Position steering wheel on steering column. Ensure flats
on steering wheel hub fit formations on inside of clockspring. Pull
clockspring, cruise control switch (if equipped) and horn wires
through lower large holes and upper small holes in steering wheel.
3) Install steering wheel retaining nut and tighten to 45 ft.
lbs. (61 N.m). Connect horn and cruise control wires (if equipped).
Connect clockspring wire to air bag module. To ensure complete
connector connection, latching arms must be visible on top of
connector housing. DO NOT connect negative battery cable at this time.
Go to SYSTEM OPERATION CHECK .
PASSENGER AIR BAG DISARM (PAD) SWITCH
Removal & Installation
1) Before proceeding, see SERVICE PRECAUTIONS. Disable air
bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM .
2) If vehicle is equipped with automatic transmission, turn
ignition switch to UNLOCK position, set parking brake and place
transmission selector lever in LOW position. Tilt steering column to
lowest position (if equipped). Using trim stick, gently pry around
perimeter of cluster bezel and remove bezel.
3) 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.
4) Reach through glove box opening to access and disconnect 2
passenger-side air bag disarm switch harness connectors. Connectors
are attached to bracket located on inboard glove box opening
reinforcement. See Fig. 4. Remove 3 screws retaining passenger-side
air bag disarm switch bezel to instrument panel.

Requested WARM boot or User-Requested COLD boot. If DRB should display
any other error message, record entire display and contact
manufacturer.
2) If DRB does not power-up, check for loose cable
connections or a bad cable. Check vehicle battery voltage (data link
connector terminal No. 16). A minimum of 11 volts is required to
adequately power DRB.
3) If all connections are proper between DRB and vehicle or
other devices, and vehicle battery is fully charged, an inoperative
DRB may be result of faulty cable or vehicle wiring.
ENTERING ON-BOARD DIAGNOSTICS
1) Before entering on-board diagnostics, refer to
PRETEST INSPECTION & DIAGNOSTIC PROCEDURE . Connect DRB to data link
connector. Data link connector (DLC) is located under left side of
instrument panel, left of steering column.
NOTE: Read active DTCs with PAD switch in both ON and OFF
positions. Always turn ignition off before changing PAD
switch positions,
2) Turn ignition switch to ON position. Exit vehicle with
DRB. Using DRB, read and record active Diagnostic Trouble Code (DTC)
data. Read and record stored DTC data. If any DTCs (fault messages)
exist, perform appropriate test.
3) If PAD switch OFF indicator fails to illuminate when in
the OFF position, go to PAD SWITCH INDICATOR PROBLEMS . If PAD switch
OFF indicator illuminates when switch is in ON position or key
cylinder does not operate, replace PAD switch.
4) Air Bag Control Module (ACM) may report any of the
following DTCs or fault messages. If the following active or stored
codes are reported by DRB, replace ACM. See
AIR BAG CONTROL MODULE (ACM) under REMOVAL & INSTALLATION.
* ACM OUTPUT DRIVER CIRCUIT OPEN
* ACM ACCELEROMETER
* ACM INTERNAL DIAGNOSTIC CODE #1
* WARNING LAMP DRIVER ERROR
* FIRING CAPACITOR LOW
* LOGIC CAPACITOR LOW
* SAFING SENSOR SHORTED
If the following active codes are reported by DRB, go to the
appropriate procedure under DIAGNOSTIC TESTS.
* CLUSTER MESSAGE MISMATCH
* DRIVER SQUIB CIRCUIT OPEN
* DRIVER SQUIB CIRCUIT SHORTED
* DRIVER SQUIB CIRCUIT SHORTED TO BATTERY
* DRIVER SQUIB CIRCUIT SHORTED TO GROUND
* LOSS OF IGNITION RUN ONLY
* LOSS OF IGNITION RUN/START
* NO CLUSTER CCD MESSAGE
* NO CCD COMMUNICATION
* MISSING OR INVALID VIN
* PASSENGER SQUIB CIRCUIT OPEN
* PASSENGER SQUIB CIRCUIT SHORTED
* PASSENGER SQUIB CIRCUIT SHORTED TO BATTERY
* PASSENGER SQUIB CIRCUIT SHORTED TO GROUND
* SCTM FAILURE
* SCTM MESSAGE MISMATCH
* VIN MESSAGE MISMATCH

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) Disconnect battery and wait 2 minutes before proceeding.
Disconnect driver-side air bag module squib connector. Connect a
jumper wire between driver-side air bag (squib) 2-pin connector
terminal No. 1 (Black/Light Blue wire) and terminal No. 2 (Dark
Green/Light Blue wire). Turn ignition on (engine off). Reconnect
battery. Using DRB, read active codes. If DRB displays DRIVER SQUIB
CIRCUIT SHORTED, replace driver-side air bag module. If not, go to
next step.
2) Disconnect clockspring 2-pin connector. Connect a jumper
wire between clockspring 2-pin connector terminals No. 1 (Black/Light
Blue wire) and No. 2 (Dark Green/Light Blue wire). Using DRB, read
active codes. If DRB displays DRIVER SQUIB CIRCUIT SHORTED, replace
clockspring. If not, go to next step.
3) Disconnect battery and wait 2 minutes before proceeding.
Remove jumper wires. Disconnect ACM connector. ACM is located under
instrument panel, on transmission tunnel. Using an ohmmeter, check
resistance between ACM connector terminal No. 6 (Dark Green/Light Blue
wire) and clockspring 2-pin connector terminal No. 2 (Dark Green/Light\
Blue wire). If resistance is less than 5 ohms, go to next step. If
resistance is more than 5 ohms, repair open or high resistance in Dark
Green/Light Blue wire.
4) Check resistance between ACM connector terminal No. 5
(Black/Light Blue wire) and clockspring 2-pin connector terminal No. 1\
(Black/Light Blue wire). If resistance is less than 5 ohms, go to next\
step. If resistance is more than 5 ohms, repair open or high
resistance in Black/Light Blue wire.
5) 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 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) Disconnect battery and wait 2 minutes before proceeding.
Ensure driver-side air bag module connector is completely connected
before disconnecting it. If driver-side air bag module connector is
not completely connected, reconnect it. If driver-side air bag
connector is completely connected, go to next step.
2) Disconnect driver-side air bag module. Turn ignition on
(engine off). Reconnect battery. Using DRB, read active codes. If DRB
displays DRIVER SQUIB CIRCUIT OPEN, replace driver-side air bag
module. If not, go to next step.
3) Disconnect clockspring 2-pin connector. Using DRB, read
active codes. If DRB displays DRIVER SQUIB CIRCUIT OPEN, replace
clockspring. If not, go to next step.
4) Turn ignition off, disconnect battery and wait 2 minutes
before proceeding. Disconnect passenger-side air bag module connector.
Using an ohmmeter, check resistance between clockspring 2-pin
connector terminal No. 1 (Black/Light Blue wire) and passenger-side
air bag 2-pin connector terminal "A" (Black/Yellow wire). If
resistance is less than 5 ohms, repair short between Black/Light Blue
wire and Black/Yellow wire. If resistance is more than 5 ohms, go to

CTM has remote keyless entry receiver and control logic incorporated.
COMPONENT TESTS
RELAYS
NOTE: Headlight relay may also be referred to as the security
relay. On Ram Pickup, the headlight relay is located in Power
Distribution Center (PDC) in engine compartment. On Ram Van
and Ram Wagon, the headlight relay is taped to headlight
switch harness. On Ram Pickup, the horn relay is located in
Power Distribution Center (PDC) in engine compartment. On Ram\
Van and Ram Wagon, the horn relay is located in junction
block under left side of instrument panel. For circuit
testing, see WIRING DIAGRAMS.
Headlight Relay & Horn Relay
Remove relay to be tested. Measure resistance between
appropriate relay terminals with relay de-energized and energized. See
RELAY TEST SPECIFICATIONS table. See Fig. 1. If continuity or
resistance is not as specified, replace relay.
RELAY TEST SPECIFICATIONS









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Terminals Condition
De-Energized
87A & 30 .............................................. Continuity
87 & 30 ............................................ No Continuity
85 & 86 .................................... 70-80 Ohms Resistance
Energized ( 1)
87 & 30 ............................................... Continuity
87A & 30 ........................................... No Continuity
( 1) - Apply position battery voltage to terminal No. 85 and ground
terminal No. 86.









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Fig. 1: Identifying Relay Connector Terminals
Courtesy of Chrysler Corp.
SYSTEM TESTS

For Vehicle Theft Security System (VTSS) testing procedures,
see appropriate BODY CONTROL COMPUTER TESTS article.
REMOVAL & INSTALLATION
CENTRAL TIMER MODULE (CTM)
NOTE: Before removing Central Timer Module (CTM), use scan tool to
view settings for programmable features. Use these settings
to program replacement CTM.
Removal & Installation (Ram Pickup)
1) Disconnect negative battery cable. Remove left underdash
cover and knee bolster reinforcement. Remove 2 CTM retaining screws at
right side of underdash opening. See Fig. 2.
2) Slide CTM down into opening far enough to gain access to
connectors. Disconnect harness connectors and remove CTM from
underdash. To install, reverse removal procedure. Reprogram new CTM.
See appropriate BODY CONTROL COMPUTER TESTS article.
Removal & Installation (Ram Van & Ram Wagon)
1) Disconnect negative battery cable. Remove left underdash
cover and knee bolster reinforcement. Remove 3 CTM retaining screws
from left center instrument panel support. See Fig. 3.
2) Slide CTM away from mounting enough to gain access to
connectors. Disconnect harness connectors and remove CTM from
underdash. To install, reverse removal procedure. Reprogram new CTM.
See appropriate BODY CONTROL COMPUTER TESTS article.
Fig. 2: Identifying CTM Location (Ram Pickup)
Courtesy of Chrysler Corp.