1999 DODGE RAM warning

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

TORQUE SPECIFICATIONS








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Application Ft. Lbs. (N.m)
Steering Wheel Nut ............................... 45 (61)
INCH Lbs. (N.m)
ACM Mounting Screws &
Support Bracket Nuts ........................ 125 (14.0)
Driver-Side Air Bag Module Screws .......... 80-100 (9-11)
Front Impact Sensor Screws ............... 40-50 (4.5-5.6)
PAD Switch Mounting Screws ...................... 20 (2.2)
Passenger-Side Air Bag Module Screws ............ 80 (9.0)









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DIAGNOSIS & TESTING
* PLEASE READ THIS FIRST *
WARNING: Always follow air bag service precautions to avoid air bag
deployment and possible personal injury. Refer to procedure
under 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.
NOTE: Although other scan tools are available, manufacturer
recommends using Diagnostic Readout Box (DRB) tester to
access SRS on-board diagnostics. Following diagnosis and
testing procedures are designed for use with DRB.
SELF-DIAGNOSTIC SYSTEM
SRS is monitored by Air Bag Control Module (ACM). ACM
contains safing sensor, an integral sensor in circuitry of system,
which is used to deploy air bag modules.
ACM monitors critical input and output circuits within air
bag system, ensuring they operate correctly. Some circuits are tested
continuously; others are checked under certain conditions. ACM
provides information about air bag system, through AIR BAG warning
light and DRB tester. Each circuit monitored by ACM has a
corresponding fault code or fault message assigned to it.
Active Codes
A code becomes active as soon as a malfunction is detected.
An active trouble code indicates an on-going malfunction. This means
the defect is currently there every time the ACM checks that
circuit/function. An active trouble code can not be erases. Active
codes will automatically erase when the reason for the code has been
corrected.
With the exception of warning light trouble codes or
malfunctions, when a malfunction is detected, AIR BAG warning light
remains illuminated for a minimum of 12 seconds or as long as the
malfunction is present.
Stored Codes
Trouble codes are automatically stored in ACM memory as soon

as the malfunction is detected. A stored code indicates there was an
active code present at some time. However, the code currently may not
be present as an active code, although another active code could be.
When a trouble code occurs, the AIR BAG warning light
illuminates for 12 seconds minimum (even if problem existed for less
than 12 seconds). Code is stored, along with time in minutes it was
active, and number of times ignition has been cycled since problem was
detected.
When and if malfunction ceases to exist, an ignition cycle
count will be initiated for that code. If ignition cycle count reaches
100 without a reoccurrence of the same malfunction, DTC is erased and
that ignition cycle counter is reset to zero. If malfunction reoccurs
before count reaches 100, ignition cycle counter will be reset and DTC
will continue to be a stored code.
If a particular code is not active while performing
diagnostic test for that code, code diagnostic test may not locate the
source of the problem. In this case, stored code can only indicate an
area of system to inspect.
If no obvious problems are found, erase stored codes, and
with ignition on, wiggle wiring harness and connectors. Recheck for
codes periodically as you work through system. This procedure may
uncover a difficult problem to locate.
PRETEST INSPECTION & DIAGNOSTIC PROCEDURE
Following precautions and procedures must be followed:
* Always follow air bag service precautions to avoid air bag
deployment and possible personal injury. Refer to procedure
under See SERVICE PRECAUTIONS.
* After component replacement, ensure proper system operation.
See SYSTEM OPERATION CHECK .
* When testing voltage or continuity at ACM, use terminal side
(not wire end) of connector. DO NOT probe wire through
insulation.
* Always check if any TECH SERVICE BULLETINS (TSBs) apply to
vehicle.
* When using diagnostic charts, DO NOT skip any steps in chart
or incorrect diagnosis may result. Always perform
SYSTEM OPERATION CHECK after repairs are made.
* Always use most current DRB diagnostic program cartridge
available to prevent erroneous codes or test results.
* When using diagnostic charts, use DRB voltmeter unless
instructed to use an external voltmeter. Never use a test
light in place of a voltmeter.
* When performing electrical tests, prevent accidental
shorting of terminals. Such shorts can damage fuses or
components and may cause a second code (message) to be
set, making diagnosis of original problem more difficult.
* Vehicle must have a fully-charged battery and functional
charging system.
* 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.
* Always disconnect DRB after use.
* Always disconnect DRB before charging battery.
USING DRB
1) Refer to DRB user guide for instructions and assistance
with reading trouble codes and other DRB functions. Under normal
operation DRB will display one of only 2 error messages: User-

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

* WARNING LAMP CIRCUIT OPEN/SHORTED
DIAGNOSTIC TESTS
* PLEASE READ THIS FIRST *
NOTE: Many of the diagnostic tests of the air bag restraint system
require voltage or resistance checks at various system
connector terminals. See Figs. 6-19.
Fig. 6: Identifying Powertrain Control Module (PCM) Connector
Terminals
Courtesy of DaimlerChrysler Corp.
Fig. 7: Identifying Instrument Cluster 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

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 ELECRO/MECH 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, MONITORS,
AND WARNING LAMP STATUS to read lamp messages from cluster. If ACM
lamp request displays NO RESP, replace ACM. If ACM lamp request does
not display NO RESP, go to next step.
3) Disconnect battery and wait 2 minutes before proceeding.
Disconnect ACM 23-pin connector. Disconnect mechanical instrument
cluster Black connector "A". Go to next step.
4) Using an ohmmeter, check resistance between mechanical
instrument cluster Black connector "A" terminal No. 9 (White/Black
wire) and ACM connector terminal No. 22 (White/Black wire). Also,
check resistance between mechanical instrument cluster Black connector
"A" terminal No. 10 (Violet/Brown wire) and ACM connector terminal No.\
21 (Violet/Brown wire). Go to next step.
5) If resistance is less than 5 ohms on both circuits,
replace instrument cluster. If resistance is more than 5 ohms on both
circuits, repair open in CCD bus circuit(s).
PASSENGER SQUIB CIRCUIT OPEN
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.
Disconnect passenger-side air bag module. Connect a jumper wire
between passenger-side air bag module 2-pin connector terminals "A"
(Black/Yellow wire) and "B" (Dark Green/Yellow wire). Turn ignition
on. Reconnect battery. Using DRB, read active codes. If DRB displays
PASSENGER SIDE SQUIB SHORT, replace passenger-side air bag module. If
not, go to next step.
2) Remove jumper wire. Disconnect battery and wait 2 minutes
before proceeding. Disconnect ACM connector. Disconnect PAD switch 4-
pin connector. Using an ohmmeter, check resistance between passenger-
side air bag module 2-pin connector terminal "A" (Black/Yellow wire)
and PAD switch 4-pin connector (harness side) terminal No. 3
(Black/Yellow 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/Yellow wire.
3) Using an ohmmeter, check resistance between PAD switch 4-
pin connector (harness side) terminal No. 3 (Black/Yellow wire) and
passenger-side air bag module 2-pin connector terminal "B" (Dark
Green/Yellow wire). If resistance is more than 5 ohms, repair open or
high resistance in Dark Green/Yellow wire. If resistance is less than
5 ohms, go to next step.
4) Using an ohmmeter, check resistance between PAD switch 4-
pin connector (harness side) terminals No. 2 (Violet/Yellow wire) an\
d
No. 4 (Dark Green/Yellow wire). Also, check resistance between PAD
switch 4-pin connector (harness side) terminals No. 1 (Brown/Yellow

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