1999 DODGE RAM Ground

step.
4) Observe AIR BAG warning light. Turn ignition off and wait
5 minutes. After 5 minutes, turn ignition on (engine off). If AIR BAG
warning light comes on for 6 to 8 seconds, replace ACM. If AIR BAG
warning light does not come on for 6 to 8 seconds, replace instrument
cluster.
REPAIRING PAD SWITCH
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, read active DTCs. If DRB displays LOSS OF
IGNITION RUN/START, go to LOSS OF IGNITION RUN/START. If DRB does not
display LOSS OF IGNITION RUN/START, go to next step.
2) Disconnect PAD switch 2-pin connector. Using a voltmeter,
check voltage between PAD switch 2-pin connector terminals No. 1
(Light Green/Yellow wire) and No. 2 (Black wire). If voltage is less\
than 10 volts, repair open in Light Green/Yellow wire. If voltage is
more than 10 volts, go to next step.
3) Turn ignition off. Using an ohmmeter, check resistance
between ground and PAD switch connector terminal No. 2 (Black wire).
If resistance is more than 5 ohms, repair open in Black wire. If
resistance is less than 5 ohms, replace PAD switch.
PAD SWITCH INDICATOR PROBLEMS
1) If PAD switch off indicator fails to illuminate in OFF
position, go to next step. If PAD switch off indicator does not fail
to illuminate in OFF position, go to step 5).
2) Using DRB, read active DTCs. If DRB displays LOSS OF
IGNITION RUN/START, go to diagnostic test for that DTC. If DRB does
not display LOSS OF IGNITION RUN/START, go to next step.
3) Disconnect PAD switch 2-pin connector. Turn ignition on.
Measure voltage between ground and PAD switch 2-pin connector Light
Green/Yellow wire. If voltage is more than 10 volts, go to next step.
If voltage is less than 10 volts, repair open in Light Green/Yellow
wire.
4) Turn ignition off. Measure resistance between ground and
PAD switch 2-pin connector Black/Pink wire. If resistance is less than
5 ohms, replace PAD switch. If resistance is more than 5 ohms, repair
open in Black/Pink wire.
5) Ensure battery is fully charged. Using DRB, read and
record both active and stored code(s). Erase stored codes. Check for
active DTC(s) in either PAD switch position. If PAD switch off
indicator illuminates in ON position, replace PAD switch. If PAD
switch off indicator does not illuminate in ON position, test
complete.
AIR BAG VERIFICATION TEST
1) Remove all jumper wires. Reconnect all previously
disconnected components (except battery). Turn ignition on and
reconnect battery. Connect DRB to data link connector. Using DRB,
erase stored codes.
2) Turn ignition off and wait 15 seconds before turning
ignition on. Wait one minute. Read active codes. If DRB displays any
active codes, perform appropriate diagnostic test. If DRB does not
display any active codes, go to next step.

3) Using DRB, read stored codes. If DRB displays stored
codes, perform appropriate diagnostic test. If DRB does not display
any stored codes, system is operating properly at this time.
COMPONENT VERIFICATION TEST
Reconnect all previously disconnected components and
connectors. Turn ignition on (engine off). Fully operate system that
was malfunctioning. If system operates properly, repair is complete.
If system does not operate properly, go to appropriate diagnostic
test.
VEHICLE COMMUNICATIONS
VEHICLE COMMUNICATION PROBLEMS
NOTE: Use this test only when instructed to do so by another
diagnostic test. Due to manufacturer changes in wire
colors, use terminal identification whenever possible.
DRB Blank Screen
If DRB Screen is blank, disconnect DRB from data link
connector. Ensure good ground exists at data link connector terminal
No. 4 (Black/Tan wire). Ensure 12-volts exists at data link connector
terminal No. 16 (Pink wire). If 12-volts does not exist, check for
blown fuse No. 12 located in power distribution center. If no problems
can be found, try a different DRB cable and/or a different DRB.
No Response Condition
If no response condition from Air Bag Control Module (ACM)
exists, go to NO RESPONSE FROM AIR BAG CONTROL MODULE .
NO RESPONSE FROM AIR BAG CONTROL MODULE
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
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) Remove and inspect fuse No. 19. If fuse is blown, go to
OPEN FUSED IGNITION SWITCH OUTPUT (RUN/START) CKT . If not, go to next
step.
2) Using a voltmeter, measure ignition switch output
RUN/START at fuse No. 19. See WIRING DIAGRAMS. If voltage is more than
10 volts, go to next step. If voltage is less than 10 volts, repair
open ignition switch output RUN/START circuit.
3) Turn ignition off and wait 2 minutes. Disconnect ACM
connector. Reinstall fuse No. 19. Turn ignition on (engine off). Using\
a voltmeter, check voltage at ACM connector terminal No. 14 (Light
Green/Yellow wire). If voltage is more than 10 volts, go to next step.
If voltage is less than 10 volts, repair open in Light Green/Yellow
wire.
4) Turn ignition off. Using DRB in ohmmeter mode, check
resistance at ACM connector terminal No. 4 (Black/Pink wire). If
resistance is more than 5 ohms, repair open in Black/Pink wire. If
resistance is less than 5 ohms, go to next step.
5) Turn ignition on (engine off). Using DRB in voltmeter
mode, check voltage at ACM connector terminal No. 21 (Violet/Brown
wire). If voltage is 1.8-2.6 volts, go to next step. If voltage is not
1.8-2.6 volts, repair open in Violet/Brown wire.

6) Using DRB in voltmeter mode, check voltage at ACM
connector terminal No. 22 (White/Black wire). If voltage is 1.8-2.6
volts, replace ACM. If voltage is not 1.8-2.6 volts, repair open in
White/Black wire.
OPEN FUSED IGNITION SWITCH OUTPUT (RUN/START) CKT
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
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) Turn ignition on (engine off). Using DRB in voltmeter
mode, probe output side (Dark Blue wire) of fuse No. 19 located in
junction block. If voltage is less than 10 volts, repair open in Dark
Blue wire. If voltage is more than 10 volts, go to next step.
2) Turn ignition off and wait 2 minutes before proceeding.
Using DRB in ohmmeter mode, probe fused side (Light Green/Yellow wire)\
of fuse No. 19 located in junction block. If resistance is less than 5
ohms, go to next step. If resistance is more than 5 ohms, go to step
4).
3) Disconnect ACM connector. Using DRB in ohmmeter mode,
probe fused side (Light Green/Yellow wire) of fuse No. 19 located in
junction block. If resistance is less than 5 ohms, repair short to
ground in Light Green/Yellow wire an replace fuse No. 19. If
resistance is more than 5 ohms, replace ACM and fuse No. 19.
4) Turn ignition off and wait 2 minutes before proceeding.
Disconnect ACM. Using an ohmmeter, check resistance between ACM
connector terminal No. 14 (Light Green/Yellow wire) and fused side
(Light Green/Yellow wire) of fuse No. 19 located in junction block. If\
resistance is more than 5 ohms, repair open in Light Green/Yellow wire
and replace fuse No. 19. If resistance is less than 5 ohms, go to next
step.
5) Reconnect ACM connector. Turn ignition on (engine off).
replace fuse No. 19. Perform appropriate diagnostic test under
DIAGNOSTIC TESTS.
NO RESPONSE FROM POWERTRAIN CONTROL MODULE
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
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 engine does not run, repair as required. If engine
runs, disconnect Powertrain Control Module (PCM) connectors. Connect a\
jumper wire between ground and PCM Gray connector terminal C30
(Violet/Brown wire). Using DRB, perform CCD bus test. If DRB does not
display SHORT TO GROUND, repair open Violet/Brown wire. If DRB
displays SHORT TO GROUND, go to next step.
2) Connect a jumper wire between ground and PCM Gray
connector terminal C28 (White/Black wire). Using DRB, perform CCD bus
test. If DRB does not display SHORT TO GROUND, repair open White/Black
wire. If DRB displays SHORT TO GROUND, replace PCM.
REPAIRING SHORT TO BATTERY
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
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) Ensure ignition switch is in the RUN position. Disconnect
Powertrain Control Module (PCM) connectors. If DRB does not display
BUS SHORT TO BATTERY, to step 8). If DRB displays BUS SHORT TO
BATTERY, go to next step.
2) Disconnect instrument cluster connectors. If DRB does not
display BUS SHORT TO BATTERY, replace instrument cluster. If DRB
displays BUS SHORT TO BATTERY, go to next step.
3) Turn ignition off and wait 2 minutes before proceeding.
Disconnect air bag control module connector. Turn ignition on (engine
off). If DRB does not display SHORT TO BATTERY, replace ACM. If DRB
displays SHORT TO BATTERY, go to next step.
4) Disconnect Central Timer Module (CTM) 18-pin connector. I\
f
DRB does not display BUS SHORT TO BATTERY, replace CTM. If DRB
displays BUS SHORT TO BATTERY, go to next step.
5) Disconnect anti-lock brake controller. If DRB does not
display BUS SHORT TO BATTERY, replace anti-lock brake controller. If
DRB displays BUS SHORT TO BATTERY, go to next step.
6) Disconnect DRB from Data Link Connector (DLC). Using a
voltmeter, check voltage between ground and DLC connector terminal No.
3 (Violet/Brown wire). If voltage is more than 0.2 volt, repair short
in Violet/Brown wire. If voltage is less than 0.2 volt, go to next
step.
7) Using a voltmeter, check voltage between ground and DLC
connector terminal No. 11 (White/Black wire). If voltage is more than
0.2 volt, repair short in White/Black wire. If voltage is less than 0.
2 volt, replace DRB or DRB cable as necessary.
8) Turn ignition off. Using an ohmmeter, check resistance
between ground and PCM Black connector terminal A31 (Black/Tan wire).
If resistance is more than 10 ohms, repair open in Black/Tan wire). If
resistance is less than 10 ohms, go to next step.
9) Using an ohmmeter, check resistance between ground and PCM
Black connector terminal A32 (Black/Tan wire). If resistance is more
than 10 ohms, repair open in Black/Tan wire). If resistance is less
than 10 ohms, replace Powertrain Control Module (PCM).
NO RESPONSE FROM INSTRUMENT CLUSTER
NOTE: Perform COMPONENT VERIFICATION TEST under DIAGNOSTIC TESTS
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) Remove Instrument cluster. Using DRB, turn on INTERNAL BUS
BIAS under SYSTEM MONITORS CCD BUS VOLTAGE. Connect a jumper wire from
Black instrument cluster 10-pin connector "A" terminal No. 9
(White/Black wire) to ground. Observe CCD BUS voltage on DRB. If
voltage did not drop to about zero volt, repair open in White/Black
wire. If voltage drops to about zero volt, go to next step.
2) Leave internal DRB CCD BUS BIAS turned on. Connect a
jumper wire from ground to Black instrument cluster 10-pin connector
"A" terminal No. 10 (Violet/Brown wire). Go to next step.
3) Observe CCD BUS voltage on DRB. If voltage did not drop to
about zero volt, repair open in Violet/Brown wire. If voltage drops to
about zero volt, replace instrument cluster.

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

The PCM contains a self-diagnostic system used for
determining an electronic component failure. The PCM self-diagnostic
system will store a Diagnostic Trouble Code (DTC) in PCM memory if
certain electronic problems are present.
DTCs can be retrieved using appropriate scan tool. See SELF-
DIAGNOSTIC SYSTEM. After repairing an electronic system problem,
stored DTC must be cleared from PCM memory. For PCM location, see PCM
LOCATION table.
AB Body
On firewall, near wiper motor.
AN & DN Bodies
Right front fender, near air cleaner.
BR Body
Right front fender, near firewall.
WJ Body
On firewall, near speed control servo.
GOVERNOR PRESSURE SENSOR
NOTE: Governor pressure sensor may also be referred to as governor
pressure transducer.
Governor pressure sensor delivers an output signal to the PCM
indicating the output pressure of governor pressure solenoid. The PCM
uses this signal to control governor pressure. Governor pressure
solenoid is located on valve body. See Fig. 1.
GOVERNOR PRESSURE SOLENOID
Governor pressure solenoid generates governor pressure
required for transmission upshifts and downshifts. Governor pressure
solenoid is located on valve body. See Fig. 1. Inlet side of governor
pressure solenoid is exposed to normal transmission line pressure and
outlet side provides a passage to governor circuit in the valve body.
Governor pressure solenoid regulates transmission line pressure to the
governor circuit. Electrical supply voltage is supplied to governor
pressure solenoid by PCM. The PCM controls the ground circuit to
governor pressure solenoid to provide solenoid operation.
Fig. 1: Identifying Governor Pressure Solenoid, Governor Pressure
Sensor & Transmission Fluid Temperature Sensor
Courtesy of DaimlerChrysler Corp.
OD (OVERDRIVE) OFF SWITCH

stretched, cut or pinched wiring. Ensure electrical connectors fit
tightly and are not corroded. Check PCM, sensors and switches for
physical damage. Check engine coolant level. Check transmission fluid
level and condition.
SELF-DIAGNOSTIC SYSTEM
* PLEASE READ THIS FIRST *
NOTE: Only transaxle-related trouble codes are listed. For engine-
related DTC definitions, see TROUBLE CODE DEFINITIONS article
in APPLICATIONS & IDENTIFICATION. For engine-related DTC
diagnosis, see appropriate SELF-DIAGNOSTICS article in ENGINE
PERFORMANCE. Engine performance DTCs must be repaired first,
as engine performance and related component signals will
affect transaxle operation and diagnosis.
DIAGNOSTIC PROCEDURE
When performing vehicle diagnosis:
* Ensure transmission fluid level is correct and fluid is
neither contaminated or aerated.
* Ensure shift cable is properly adjusted. See appropriate
AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION
SERVICING.
* Ensure battery is fully charged.
* Perform visual inspection, ensuring all electrical
connections at transmission, PCM, TP sensor and output shaft
speed sensor are clean and properly installed.
* Retrieve DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES.
* Repair DTCs in order displayed.
* Always perform test verification test after any repair
procedure is completed unless specified otherwise. See
appropriate verification test under DIAGNOSTIC TESTS.
NOTE: Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB) scan tool. A generic scan tool
may be used, but may not be capable of performing all
necessary test functions.
TEST EQUIPMENT HOOK-UP
Generic Scan Tool & DVOM
Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB) scan tool. The DRB has a built-in DVOM
function. A generic scan tool may be used, but may not be capable of
performing all necessary test functions. If DRB test procedures
require resistance or voltage to be measured using scan tool in
ohmmeter or voltmeter mode, connect DVOM ground lead to DLC connector
terminal No. 4 and positive lead to terminal specified in test
procedure.
DRB Scan Tool
Refer to DRB scan tool instructions to read and clear DTCs,
and when performing other scan tool functions. DRB scan tool is
grounded through DLC connector terminal No. 4. Only one volt/ohmmeter
test lead is required to measure voltage or resistance. See Fig. 2.
RETRIEVING DIAGNOSTIC TROUBLE CODES
NOTE: Manufacturer recommends using Chrysler's Diagnostic Readout

* PLEASE READ THIS FIRST *
NOTE: For engine-related DTCs, see appropriate SELF-DIAGNOSTICS
article in ENGINE PERFORMANCE. Engine performance DTCs must
be repaired first, as engine performance and related
component signals will affect transmission operation and
diagnosis.
All references to Using scan tool, perform TCC SYSTEM TEST
are for scan tool driven testing of TCC system. Follow manufactures
scan tool instructions.
All connector references in the following testing apply to
harness connectors unless otherwise specified. For circuit, wire color
and connector terminal identification, see CONNECTOR IDENTIFICATION
and WIRING DIAGRAMS. After all repairs are complete or any component
is replaced, perform verification test as follows:
* DTC P0751 perform appropriate verification VER-2A.
* All DTCs except P0751 perform appropriate verification
VER-5A.
DTC P0711: TRANS TEMP SENSOR, NO TEMP RISE AFTER START
NOTE: To test transmission temperature sensor, engine and
transmission temperature must be less than 85F (29C).
1) Using scan tool, read DTCs. If DTCs P0712, P0713 or P1899
are present, repair these DTCs before proceeding. If neither of these
DTCs are present, go to next step.
2) Using scan tool, read and record Engine Coolant
Temperature (ECT) sensor temperature, and transmission temperature
sensor temperature. If transmission temperature is within 9
F (-13C)
of ECT temperature, go to step 5). If transmission temperature is not
within 9
F (-13C) of ECT temperature, go to next step.
3) Start engine and let it idle in gear, with brake on.
Monitor transmission temperature sensor. If transmission temperature
does not increase steadily 15
F (-9C) over a 10 minute period, go to
step 5). If transmission temperature increases steadily 15F (-9C)
over a 10 minute period, go to next step.
4) Inspect all related wiring and connectors. Repair as
necessary. If wiring and connectors are okay, see INACTIVE DTC
CONDITION under SELF-DIAGNOSTIC SYSTEM. Testing is complete.
5) Disconnect transmission solenoid harness connector.
Inspect connector and terminals for damage. Repair as necessary. If
connector and terminals are okay, replace transmission governor
pressure/temperature sensor.
DTC P0712: TRANS TEMP SENSOR VOLTAGE TOO LOW
Circuit Description
Circuit is monitored continuously while key is on, and engine
running. Code sets if transmission temperature sensor voltage is less
than 1.55 volts for 2.2 seconds.
Possible Causes
* Transmission temperature sensor wiring harness defective.
* Transmission pressure/temperature sensor defective.
* Transmission temperature signal circuit short to ground.
* Transmission temperature signal circuit short to sensor
ground circuit.
* PCM defective.