1999 DODGE RAM change time

voltage. If voltage is less than one volt, go to next step. If voltage
is one volt or more, condition to set FTC is not present at this time.
Test is complete.
2) While observing scan tool, disconnect S/C ON/OFF switch.
If S/C switch voltage changes to 5 volts, replace S/C ON/OFF switch.
Perform TEST VER-4A under VERIFICATION TESTS. If voltage does not
change to 5 volts, go to next step.
3) While observing scan tool, disconnect S/C RESUME/ACCEL
switch. If S/C switch voltage changes to 5 volts, replace S/C
RESUME/ACCEL switch. Perform TEST VER-4A under VERIFICATION TESTS. If
voltage does not change to 5 volts, go to next step.
4) Turn ignition off. Ensure both S/C switches are still
disconnected. Using an ohmmeter, check resistance between S/C switch
connector terminals (S/C switch signal circuit and S/C switch ground
circuit). If resistance is less than 5 ohms, repair short circuit.
Perform TEST VER- 4A under VERIFICATION TESTS. If resistance is 5 ohms
or more, go to next step.
5) Disconnect clockspring 4-pin connector. Clockspring 4-pin
connector is located behind steering wheel. Inspect connector. Clean
or repair as necessary. Using an ohmmeter, check resistance between
ground and S/C switch signal circuit at clockspring connector (Dark
Green/Red wire on all models except Ram Van and Ram Wagon; wire color
is not available for Ram Van and Ram Wagon). If resistance is less
than 5 ohms, repair short to ground. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is 5 ohms or more, go to next step.
6) Disconnect PCM. Inspect connectors. Clean or repair as
necessary. Using an ohmmeter, check resistance between ground and S/C
switch signal circuit at either S/C switch connector (Dark Green/Red
wire on all models except Ram Van and Ram Wagon; wire color is not
available for Ram Van and Ram Wagon). If resistance is less than 5
ohms, repair short to ground. Perform TEST VER-4A under VERIFICATION
TESTS. If resistance is 5 ohms or more, replace PCM. Perform TEST VER-
4A under VERIFICATION TESTS.
FTC P1683: SPEED CONTROL POWER RELAY CIRCUIT
FTC P1683 will set if Speed Control (S/C) power supply
circuit is open or shorted when S/C is turned on.
Possible Causes:
* Brake switch out of adjustment.
* S/C brake switch output circuit open or shorted.
* Defective S/C servo.
* Defective brake switch.
* S/C vacuum or vent solenoid control circuits open or
shorted.
* Defective PCM.
* Ground circuit open.
* S/C power supply circuit open.
NOTE: For component locations, see COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
NOTE: Ensure brake pedal is not depressed during the following
steps.
1) Turn ignition off. Disconnect S/C servo connector. Inspect
connector. Clean or repair as necessary. Turn ignition on. Using scan
tool, actuate S/C relay. Using a 12-volt test light, probe S/C brake
switch output circuit at S/C servo connector terminal No. 3 (Dark
Blue/Red wire). If test light is illuminated and bright, go to next

reusing original differential bearings and bearing races, ensure
bearing races are installed in original locations.
13) Place axle housing spreader on axle housing so dowel pins
engage with locating holes. See Fig. 1. Use Axle Housing Spreader (W-
129-B). Install hold-down clamps. Tighten turnbuckle on axle housing
spreader finger tight.
14) Install pilot stud and dial indicator on axle housing.
See Fig. 1 . Position dial indicator so stem is resting against
opposite side of axle housing, with pressure on stem.
CAUTION: DO NOT spread axle housing more than .020" (.50 mm), or axle
housing may be damaged.
15) Adjust dial indicator to zero. Tighten turnbuckle enough
to spread axle housing for differential case removal while noting
reading on dial indicator. Dial indicator reading should not exceed .
020" (.50 mm).
16) Remove dial indicator. Install differential case and
bearing races in axle housing. Ensure differential bearings and races
are fully seated. Remove axle housing spreader.
17) Install bearing caps in original location. Install
bearing cap bolts, and tighten to specification. See TORQUE
SPECIFICATIONS table. Rotate differential case several times to seat
differential bearings.
18) Using dial indicator, check ring gear backlash. See
Fig. 6 . Ensure ring gear backlash is as specified. See AXLE ASSEMBLY
SPECIFICATIONS.
19) If ring gear backlash exceeds specification, move ring
gear toward pinion. If ring gear backlash is less than specification,
move ring gear away from pinion. To change ring gear backlash, move
preload shims from one side of differential case to other.
20) Check ring gear backlash every 90 degrees to check for
variation. Ring gear backlash variation should not exceed .002" (.05
mm). For example, if ring gear backlash is .005" (.15 mm) at minimum
point, ring gear backlash should not exceed .008" (.20 mm) anywhere on\
ring gear.
Final Inspection & Assembly
1) With ring gear backlash properly adjusted, check gear
tooth pattern contact. See GEAR TOOTH CONTACT PATTERNS article in
GENERAL INFORMATION.
2) When differential is complete and correctly adjusted,
install axle housing cover using NEW gasket (if equipped). If gasket
is not available, apply a 1/4" thick bead of silicone sealant on
inside of bolt holes and along sealing surfaces on axle housing cover.
3) Install axle housing cover, axle identification tag and
retaining bolts. Tighten bolts to specification. See TORQUE
SPECIFICATIONS table. Fill differential with gear lube. See
LUBRICATION.
Fig. 6: Checking Ring Gear Backlash
Courtesy of Chrysler Corp.

bearing races in axle housing. Ensure differential bearings and races
are fully seated. Remove axle housing spreader.
17) Install bearing caps in original location. Install and
tighten bearing cap bolts to specification. See TORQUE SPECIFICATIONS
table. Rotate differential case several times to seat differential
bearings.
18) Using dial indicator, check ring gear backlash. See
Fig. 7. Ensure ring gear backlash is as specified. See AXLE ASSEMBLY
SPECIFICATIONS.
19) If ring gear backlash exceeds specification, move ring
gear toward pinion. If ring gear backlash is less than specification,
move ring gear away from pinion. To change ring gear backlash, move
preload shims from one side of differential case to other.
20) Check ring gear backlash every 90 degrees to check for
variation. Ring gear backlash variation should not exceed .002" (.05
mm). For example, if ring gear backlash is .005" (.15 mm) at the
minimum point, ring gear backlash should not exceed .007" (.18 mm)
anywhere on ring gear.
Final Inspection & Assembly
1) With ring gear backlash properly adjusted, check gear
tooth pattern contact. See GEAR TOOTH CONTACT PATTERNS article in
GENERAL INFORMATION.
2) When differential is complete and correctly adjusted,
install axle housing cover using NEW gasket (if equipped). If gasket
is not available, apply a 1/4" thick bead of silicone sealant on
inside of bolt holes and along sealing surfaces on axle housing cover.
3) Install axle housing cover, axle identification tag and
retaining bolts. Tighten bolts to proper specification. See TORQUE
SPECIFICATIONS. Fill differential with gear lube. See LUBRICATION.
Fig. 7: Checking Ring Gear Backlash
Courtesy of Chrysler Corp.
AXLE ASSEMBLY SPECIFICATIONS

during manufacture, some new type valves cannot be reground.
Resurface valve on proper angle specification using valve
grinding machine. Follow manufacturer's instructions for valve
grinding machine. Specifications may indicate a different valve face
angle than seat angle.
Measure valve margin after grinding. Replace valve if not
within specification. Valve stem tip can be refinished using valve
grinding machine.
Valve Lapping
During valve lapping of recent designed valves, be sure to
follow manufacturers recommendations. Surface hardening and materials
used with some valves do not permit lapping. Lapping process will
remove excessive amounts of the hardened surface.
Valve lapping is done to ensure adequate sealing between
valve face and seat. Use either a hand drill or lapping stick with
suction cup attached.
Moisten and attach suction cup to valve. Lubricate valve stem
and guide. Apply a thin coat of fine valve grinding compound between
valve and seat. Rotate lapping tool between the palms or with hand
drill.
Lift valve upward off the seat and change position often.
This is done to prevent grooving of valve seat. Lap valve until a
smooth polished seat is obtained. Thoroughly clean grinding compound
from components. Valve to valve seat concentricity should be checked.
See VALVE SEAT CONCENTRICITY.
CAUTION: Valve guides must be in good condition and free of carbon
deposits prior to valve seat grinding. Some engines contain
an induction hardened valve seat. Excessive material removal
will damage valve seats.
Valve Seat Grinding
Select coarse stone of correct size and angle for seat to be
ground. Ensure stone is true and has a smooth surface. Select correct
size pilot for valve guide dimension. Install pilot in valve guide.
Lightly lubricate pilot shaft. Install stone on pilot. Move stone off
and on the seat approximately 2 times per second during grinding
operation.
Select a fine stone to finish grinding operation. Grinding
stones with 30 and 60 degree angles are used to center and narrow the
valve seat as required. See Fig. 10.
Fig. 10: Adjusting Valve Seat Width - Typical
This Graphic For General Information Only
Valve Seat Replacement
Replacement of valve seat inserts is done by cutting out

interchangeable. Inspect all components for wear. Note amount of wear
in lifter body-to-camshaft contact area. Surface must have smooth and
convex contact face. If wear is apparent, carefully inspect cam lobe.
Inspect push rod contact area and lifter body for scoring
or signs of wear. If body is scored, inspect lifter bore for damage
and lack of lubrication. On roller type lifters, inspect roller for
flaking, pitting, loss of needle bearings and roughness during
rotation.
Measure lifter body O.D. in several areas. Measure lifter
bore I.D. of cylinder block. Some models offer oversized lifters.
Replace lifter if damaged.
If lifter check valve is not operating, obstructions may be
preventing it from closing or valve spring may be broken. Clean or
replace components as necessary.
Check plunger operation. Plunger should drop to bottom of the
body by its own weight when assembled dry. If plunger is not free,
soak lifter in solvent to dissolve deposits.
Lifter leak-down test can be performed on lifter. Lifter
must be filled with special test oil. New lifters contain special test
oil. Using lifter leak-down tester, perform leak-down test following
manufacturer's instructions. If leak-down time is not within
specifications, replace lifter assembly.
Lifters should be soaked in clean engine oil several hours
prior to installation. Coat lifter base, roller (if equipped) and
lifter body with ample amount of Molykote or camshaft lubricant. See
Fig. 13. Install lifter in original location. Install remaining
components. Valve lash adjustment is not required on most hydraulic
lifters. Preload of hydraulic lifter is automatic. Some models may
require adjustment.
Mechanical Lifters
Lifter assemblies must be installed in original locations.
Remove rocker arm assembly and push rod. Mark components for location.
Some applications require intake manifold or lifter cover removal.
Remove lifter retainer plate (if used). To remove lifters, use lifter
remover or magnet.
Inspect push rod contact area and lifter body for scoring or
signs of wear. If body is scored, inspect lifter bore for damage and
lack of lubrication. Note amount of wear in lifter body-to-camshaft
contact area. Surface must have smooth and convex contact face. If
wear is apparent, carefully inspect cam lobe.
Coat lifter base, roller (if equipped) and lifter body with
ample amount of Molykote or camshaft lubricant. Install lifter in
original location. Install remaining components. Tighten bolts to
specification. Adjust valves. See VALVE ADJUSTMENT in this article.
PISTONS, CONNECTING RODS & BEARINGS
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
RIDGE REMOVAL
Ridge in cylinder wall must be removed prior to piston
removal. Failure to remove ridge prior to removing pistons will cause
piston damage in piston ring locations.
With the piston at bottom dead center, place a rag in the
bore to trap metal chips. Install ridge reamer in cylinder bore.
Adjust ridge reamer using manufacturer's instructions. Remove ridge

HO W T O U SE S YSTE M W IR IN G D IA G RAM S
1999 D odge P ic ku p R 1500
GENERAL INFORMATION
Using Wiring Diagrams
All Models
INTRODUCTION
This CD obtains wiring diagrams and technical service
bulletins, containing wiring diagram changes from the domestic and
import manufacturers. These are checked for accuracy and are all
redrawn into a consistent format for easy use.
In the past, when cars were simpler, diagrams were simpler.
All components were connected by wires and diagrams seldom exceeded 4
pages in length. Today, some wiring diagrams require more than 16
pages. It would be impractical to expect a service technician to trace
a wire from page 1 across every page to page 16.
Removing some of the wiring maze reduces eyestrain and time
wasted searching across several pages. Today the majority of
these

diagrams follow a much improved format, which permits space for
internal switch details.
Wiring diagrams are drawn in a "top-down" format. The
diagrams are drawn with the power source at the top of the diagram and
the ground point at the bottom of the diagram. Components locations
are identified on the wiring diagrams. Any wires that don't connect
directly to a component are identified on the diagram to indicate
where they go.
COLOR ABBREVIATIONS
COLOR ABBREVIATIONS TABLE








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Color Normal Optional
Black ................ BLK .......................... BK
Blue ................. BLU .......................... BU
Brown ................ BRN .......................... BN
Clear ................ CLR .......................... CR
Dark Blue .......... DK BLU ...................... DK BU
Dark Green ......... DK GRN ...................... DK GN
Green ................ GRN .......................... GN
Gray ................. GRY .......................... GY
Light Blue ......... LT BLU ...................... LT BU
Light Green ........ LT GRN ...................... LT GN
Orange ............... ORG .......................... OG
Pink ................. PNK .......................... PK
Purple ............... PPL .......................... PL
Red .................. RED .......................... RD
Tan .................. TAN .......................... TN
Violet ............... VIO .......................... VI
White ................ WHT .......................... WT
Yellow ............... YEL .......................... YL









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IDENTIFYING WIRING DIAGRAM ABBREVIATIONS
NOTE: Abbreviations used on these diagrams are normally
self-explanatory. If necessary see ABBREVIATIONS

CAUTION: If fuel contamination due to fungi or other microorganisms is
suspected a fuel additive with a biocide may be used. Follow
the manufacturers dosage as recommended on product label. Use
biocides ONLY when necessary, excessive use can may cause
other fuel system problems.
DIESEL FUEL CONTAMINATION
WARNING: Diesel fuel system may be contaminated with fungi or other
microorganisms. Keep contaminated fuel away from open skin
cuts or sores to prevent skin irritation or infection.
DIESEL FUEL REQUIREMENTS
CAUTION: All diesel engines have been developed to take advantage of
the high energy content of No. 2 diesel fuel or No. 2
climatized-diesel fuels. It also operates on No. 1-diesel
fuels if temperatures are expected to be extended arctic
conditions -10
\bF (-23\bC).
WARNING: Do NOT use alcohol or gasoline as a fuel blending agent. They
can be unstable under certain conditions and hazardous or
explosive when mixed with diesel fuel.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
WARNING: Many solid state electrical components can be damaged by
static electricity (ESD). Some will display a warning label,
but many will not. Discharge personal static electricity by
touching a metal ground point on the vehicle prior to
servicing any ESD sensitive component.
ENGINE OIL
CAUTION: Never use non-detergent or straight mineral oil.
ENGINE OIL FILTER (CARTRIDGE TYPE)
CAUTION: Use of Mopar Oil Filter Cartridge (P/N 04746914) is
RECOMMENDED. The engine oil filter cartridge should be
changed at every engine oil change. Use the same type oil
that will be used in the engine.
FUEL SYSTEM SERVICE
WARNING: Relieve fuel system pressure prior to servicing any fuel
system component (fuel injection models).
HALOGEN BULBS
WARNING: Halogen bulbs contain pressurized gas which may explode if
overheated. DO NOT touch glass portion of bulb with bare
hands. Eye protection should be worn when handling or working
around halogen bulbs.
RADIATOR CAP
CAUTION: Always disconnect the fan motor when working near the
radiator fan. The fan is temperature controlled and could
start at any time even when the ignition key is in the OFF
position. DO NOT loosen or remove radiator cap when cooling
system is hot.

PCM also operates A/C compressor clutch (if A/C is requested)\
through A/C clutch relay. When engine reaches operating temperature,
vehicle will go into idle mode and PCM will begin monitoring HO2S
input and go into closed loop operation.
* Idle - When engine is at operating temperature, this is a
closed loop mode. In idle mode, PCM now adds HO2S signal to
array of inputs used in ENGINE WARM-UP mode. PCM maintains
correct air/fuel ratio by adjusting injector pulse width and
ignition timing. PCM also controls A/C clutch operation (if
A/C is requested).
* Cruise - When engine is at operating temperature, this is a
closed loop mode. Using information from A/C switch, battery
voltage, CKP sensor, ECT sensor, IAT sensor, MAP sensor and
CMP sensor. PCM also monitors A/C request and P/N switch (A/T
only), TP sensor and VSS signals for fuel calculation. PCM
monitors HO2S and adjusts air/fuel ratio as needed. PCM
controls engine idle speed through IAC motor. PCM controls
spark advance as necessary.
* Acceleration - This is an open loop mode. When PCM
recognizes an abrupt increase in throttle position or
manifold pressure as a demand for increased engine output, it
increases injector pulse width in response to increased fuel
demand. HO2S signals are ignored.
* Deceleration - This is an open loop mode when engine is at
operating temperature and under deceleration. When PCM
receives inputs signaling a closed throttle and an abrupt
decrease in manifold pressure, it reduces injector pulse
width to lean air/fuel mixture. Under certain RPM and closed
throttle position conditions, HO2S signals are ignored and
PCM cuts off fuel injection until idle speed is reached. PCM
also drives IAC motor for smooth transition to idle mode.
* Wide Open Throttle - This is an open loop mode. When PCM
senses wide open throttle, it grounds fuel injectors in
sequence, it ignores HO2S input and it controls pulse width
to supply a pre-determined amount of additional fuel. PCM
also adjusts spark advance and disengages A/C clutch for
approximately 15 seconds.
* Ignition Switch Off - This is an open loop mode. PCM drives
IAC motor into position in anticipation of next start-up. All
outputs are turned off, no inputs are monitored and PCM shuts
down.
Sequential Fuel Injection (SFI)
Individual, electrically pulsed injectors (one per cylinder)
are located in intake manifold runners. These injectors are next to
intake valves in intake manifold. PCM controls injection timing based
on crankshaft position signal input. PCM regulates air/fuel mixture by
length of time injector stays open (pulse width) based on inputs from
HO2S, ECT sensor, MAP and other sensors.
IDLE SPEED
NOTE: DO NOT attempt to correct a high idle speed condition by
turning factory sealed throttle body throttle plate set
screw. This will not change idle speed of warm engine, but
may cause cold start problems due to restricted airflow.
Idle Air Control (IAC) Motor
IAC motor adjusts idle speed to compensate for engine load
and ambient temperature by adjusting amount of air flowing through by-
pass in back of throttle body. PCM uses ECT sensor, VSS, TP sensor and