2003 DODGE RAM heater

8W-91 CONNECTOR/GROUND/SPLICE LOCATION
TABLE OF CONTENTS
page
CONNECTOR/GROUND/SPLICE LOCATION
DESCRIPTION..........................1
CONNECTOR/GROUND/SPLICE
LOCATION
DESCRIPTION
This section provides illustrations identifying con-
nector, ground, and splice locations in the vehicle.
Connector, ground, and splice indexes are provided.Use the wiring diagrams in each section for connec-
tor, ground, and splice identification. Refer to the
index for the proper figure number. For items that
are not shown in this section N/S is placed in the
Fig. column.
CONNECTORS
CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
4WD Switch (Manual Transfer
Case)BK Near T/O for Backup Lamp Switch 16
A/C Compressor Clutch BK At A/C Compressor 3, 5, 8, 9, 10
A/C Pressure Transducer BK Left Side of A/C Compressor 3, 5, 8, 9, 10
A/C-Heater Control C1 BK Center of Instrument Panel 36, 37, 38
A/C-Heater Control C2 BK Center of Instrument Panel 36, 37
Adjustable Pedal Motor WT Left of Instrument Panel 33
Adjustable Pedal Switch BL Left of Instrument Panel 37, 39
Airbag Control Module YL Lower Center of Instrument Panel 37, 38
Airbag Control Module-Left Side
ImpactYL Left B-Pillar 44, 45
Airbag Control Module-Right Side
ImpactYL Right B-Pillar N/S
Airbag-Driver Squib 1 YL On Steering Wheel 32
Airbag-Left Curtain Squib YL Top Left B-Pillar 44, 45
Airbag-Passenger Squib 1 YL Right Front of Instrument Panel 37, 40
Airbag-Right Curtain Squib YL Top Right B-Pillar N/S
Ambient Temperature Sensor BK Left Rear of Hood 31
Amplifier Audio C1 GY Top Center of Instrument Panel 37, 40
Amplifier Audio C2 GY Top Center of Instrument Panel 37, 40
Automatic Day/Night Mirror (Except
Base)BK Top Center of Windshield N/S
Backup Lamp Switch BK Left Rear of Transmission 16
Battery Temperature Sensor BK Below Battery Tray 26, 28, 29, 30
Blend Door Actuator (Single Zone) BK Behind Right Side of Instrument
PanelN/S
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 1

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Door Ajar Switch-Driver (Base) BK Left Front Door 42
Door Ajar Switch-Left Rear (Base) BK Left Rear Door 43
Door Ajar Switch-Passenger (Base) BK Right Front Door N/S
Door Ajar Switch-Right Rear (Base) BK Right Rear Door 43
Door Lock Motor/Ajar Switch-Driver
(Except Base)BK Left Front Door 42
Door Lock Motor/Ajar Switch-Left
Rear (Except Base)BK Left Rear Door 43
Door Lock Motor/Ajar Switch-
Passenger (Except Base)BK Right Front Door N/S
Door Lock Motor/Ajar Switch-Right
Rear (Except Base)BK Right Rear Door 43
Door Lock Switch-Passenger BL In Right Front Door N/S
Driver Airbag Squib BK In Steering Column N/S
Driver Blend Door Actuator (Dual
Zone)BK Right Side of HVAC N/S
Driver Door Module C1 BL In Left Front Door 42
Driver Door Module C2 BL In Left Front Door 42
Engine Control Module C1 BK Left Engine 10
Engine Control Module C2 BK Left Engine 10
Engine Coolant Temperature
SensorBK Near Generator 4, 7, 9
Engine Oil Pressure Sensor BK Lower Left Side of Engine 4, 6, 8, 9, 11
Evap/Purge Solenoid BK Left Fender Side Shield 26, 28
Evaporator Temperature Sensor BK Right Side of HVAC N/S
Fog Lamp-Left WT Left Front Facia N/S
Fog Lamp-Right WT Right Front Facia N/S
Fuel Control Actuator (Diesel) BK Left Rear Engine 23
Fuel Heater (Diesel) BK Left Side Engine 10
Fuel Injector No.1 BK At Fuel Injector 4, 8
Fuel Injector No. 2 BK At Fuel Injector 3, 7
Fuel Injector No. 3 BK At Fuel Injector 4, 8
Fuel Injector No. 4 BK At Fuel Injector 3, 7
Fuel Injector No. 5 BK At Fuel Injector 4, 8
Fuel Injector No. 6 BK At Fuel Injector 3, 7
Fuel Injector No. 7 BK At Fuel Injector 4, 8
Fuel Injector No. 8 BK At Fuel Injector 3, 7
Fuel Pump Module LT GY At Fuel Tank 48
Fuel Pump Motor (Diesel) BK Left Side Engine 10
Generator BK Front of Engine 4, 6, 7, 10
Glove Box Lamp and Switch BK At Glove Box 37, 40
Governor Pressure Sensor BK Left Rear of Transmission N/S
Headlamp Switch BK Left Side of Instrument Panel 34, 37, 39
Headlamp-Left BL At Headlamp 26, 30, 31
8W - 91 - 4 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONDR
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Headlamp-Right BL At Headlamp 1, 25, 29
Heated Seat Cushion - Driver BL Under Driver Seat N/S
Heated Seat Cushion - Passenger BL Under Passenger Seat N/S
Heated Seat Switch-Driver RD Center of Instrument Panel 35, 37, 38
Heated Seat Switch-Passenger BL Center of Instrument Panel 35, 37, 38
Horn Switch WT In Steering Wheel N/S
Horn-High Note BK Left Front Fender 26, 30, 31
Horn-Low Note BK Left Front Fender 26, 31
Idle Air Control Motor BK On Throttle Body 4, 8
Ignition Coil GY Left Rear of Engine 7, 17
Ignition Coil - Left (8.0L) BK Right Side Engine 9
Ignition Coil - Right (8.0L) BK Right Side Engine 9
Ignition Switch BK Steering Column 33
Inlet Air Temperature/Manifold
Absolute Pressure SensorBK Right Side Engine 10
Input Speed Sensor BK At Transmission 14, 15
Instrument Cluster C1 GY Rear of Instrument Cluster 37
Instrument Cluster C2 GY Rear of Instrument Cluster 37
Instrument Cluster C3 WT Rear of Instrument Cluster 39
Intake Air Heater Relay Right Engine Compartment 2
Intake Air Temperature/Manifold
Absolute Temperature Sensor
(Diesel)BK Left rear Engine N/S
Intake Air Temperature Sensor BK On Intake Manifold 4, 7, 9
Integrated Power Module C1 BK Left Front Fender 29, 30
Integrated Power Module C2 WT Left Front Fender 29, 30
Integrated Power Module C3 GR Left Front Fender 29, 30
Integrated Power Module C4 WT Left Front Fender 29, 30
Integrated Power Module C5 BK Left Front Fender 29, 30
Integrated Power Module C6 BK Left Front Fender 28, 29, 30
Integrated Power Module C7 GY Left Front Fender 29, 30
Integrated Power Module FCM BK In IPM N/S
Knock Sensor BK Left Rear of Engine 5, 6, 17
Leak Detection Pump (Except 8.0L) BK Left Middle of Chassis 48
Leak Detection Pump (8.0L) BK Left Transmission 13
License Lamp-Left BK At Rear Bumper 48, 49
License Lamp-Right BK At Rear Bumper 48, 49
Lift Pump Motor BK Near T/O for WIF Sensor N/S
Line Pressure Sensor BK Right Rear of Transmission 14, 18, 19
Lumbar Motor-Driver DK GY At Driver Seat N/S
Lumbar Motor-Passenger BK At Passenger Seat N/S
Manifold Absolute Pressure Sensor
(4.7L)GY Left Front of Intake Manifold 4
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 5
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/NUMBER COLOR LOCATION FIG.
Powertrain Control Module C2 WT Right Rear Engine Compartment 21, 22, 23, 24
Powertrain Control Module C3 GY Right Rear Engine Compartment 21, 22, 23, 24
Powertrain Control Module C4 GN Right Rear Engine Compartment 21
PTO Sense Near G107 21, 22, 24
Radio (Base) GY Rear of Radio 37, 38
Radio (Premium) BK Rear of Radio 37, 38
Recirculation Door Actuator BK Right Side of HVAC N/S
Red Brake Warning Indicator
SwitchBK Near Master Cylinder 26, 28, 31
Remote Radio Switch-Left BK At Steering Wheel N/S
Remote Radio Switch-Right BK At Steering Wheel N/S
Seat Belt Pretensioner-Left YL Left B-Pillar 44, 45
Seat Belt Pretensioner-Right YL Right B-Pillar N/S
Seat Belt Switch-Driver DK GY Left B-Pillar N/S
Seat Belt Tension Reducer
(Standard Cab)YL Left B-Pillar 44
Seat Heater Interface Module GN Under Driver Seat N/S
Sentry Key Immobilizer Module BK On Steering Column 32
Side Marker - Left Front (Dual
Wheels)BK Front of Left Rear Fender 50
Side Marker - Left Rear (Dual
Wheels)BK Rear of Left Rear Fender 50
Side Marker - Right Front (Dual
Wheels)BK Front of Right Rear Fender 50
Side Marker - Right Rear (Dual
Wheels)BK Rear of Right Rear Fender 50
Speaker-Center Instrument Panel WT Center of Instrument Panel 37, 38
Speaker-Left Front Door WT In Left Front Door 42
Speaker-Left Instrument Panel BK Left Side of Instrument Panel 37, 39
Speaker-Left Rear (Standard Cab) WT In Lower Left B-Pillar 44
Speaker-Left Rear Door (Quad
Cab)WT In Left Rear Door 43
Speaker-Right Front Door WT In Right Front Door N/S
Speaker-Right Instrument Panel BK Right Side of Instrument Panel 37, 40
Speaker-Right Rear (Standard
Cab)BK In Lower Right B-Pillar N/S
Speaker-Right Rear Door (Quad
Cab)BK In Right Rear Door 43
Speed Control Servo BK Left Front Side of Engine
Compartment26, 28
Speed Control Switch - Left
(Except ETC)GN Steering Wheel N/S
Speed Control Switch - Right
(Except ETC)GN Steering Wheel N/S
Speed Control Switch-Left (ETC) WT At Steering Wheel N/S
DR8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 7
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

of oil and coolant. Can be used on threaded and
machined parts under all temperatures. This mate-
rial is used on engines with multi-layer steel (MLS)
cylinder head gaskets. This material also will pre-
vent corrosion. MopartGasket Sealant is available in
a 13 oz. aerosol can or 4oz./16 oz. can w/applicator.
FORM-IN-PLACE GASKET AND SEALER
APPLICATION
Assembling parts using a form-in-place gasket
requires care but it's easier than using precut gas-
kets.
MopartGasket Maker material should be applied
sparingly 1 mm (0.040 in.) diameter or less of sealant
to one gasket surface. Be certain the material sur-
rounds each mounting hole. Excess material can eas-
ily be wiped off. Components should be torqued in
place within 15 minutes. The use of a locating dowel
is recommended during assembly to prevent smear-
ing material off the location.
MopartEngine RTV GEN II or ATF RTV gasket
material should be applied in a continuous bead
approximately 3 mm (0.120 in.) in diameter. All
mounting holes must be circled. For corner sealing, a
3.17 or 6.35 mm (1/8 or 1/4 in.) drop is placed in the
center of the gasket contact area. Uncured sealant
may be removed with a shop towel. Components
should be torqued in place while the sealant is still
wet to the touch (within 10 minutes). The usage of a
locating dowel is recommended during assembly to
prevent smearing material off the location.
MopartGasket Sealant in an aerosol can should be
applied using a thin, even coat sprayed completely
over both surfaces to be joined, and both sides of a
gasket. Then proceed with assembly. Material in a
can w/applicator can be brushed on evenly over the
sealing surfaces. Material in an aerosol can should be
used on engines with multi-layer steel gaskets.
STANDARD PROCEDURE - ENGINE GASKET
SURFACE PREPARATION
To ensure engine gasket sealing, proper surface
preparation must be performed, especially with the
use of aluminum engine components and multi-layer
steel cylinder head gaskets.
Neveruse the following to clean gasket surfaces:
²Metal scraper
²Abrasive pad or paper to clean cylinder block
and head
²High speed power tool with an abrasive pad or a
wire brush (Fig. 2)
NOTE: Multi-Layer Steel (MLS) head gaskets require
a scratch free sealing surface.
Only use the following for cleaning gasket surfaces:²Solvent or a commercially available gasket
remover
²Plastic or wood scraper (Fig. 2)
²Drill motor with 3M RolocŸ Bristle Disc (white
or yellow) (Fig. 2)
CAUTION: Excessive pressure or high RPM (beyond
the recommended speed), can damage the sealing
surfaces. The mild (white, 120 grit) bristle disc is
recommended. If necessary, the medium (yellow, 80
grit) bristle disc may be used on cast iron surfaces
with care.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove hood. Mark hood hinge location for
reinstallation.
(3) Remove air cleaner assembly.
(4) Remove radiator core support bracket.
(5) Remove fan shroud with viscous fan assembly.
(6) Remove drive belt.
(7) Remove A/C compressor and secure away from
engine.
(8) Remove generator and secure away from
engine.
NOTE: Do NOT remove the phenolic pulley from the
P/S pump. It is not required for P/S pump removal.
(9) Remove power steering pump with lines
attached and secure away from engine.
(10) Drain cooling system.
(11) Disconnect the heater hoses from the engine.
Fig. 2 Proper Tool Usage For Surface Preparation
1 - ABRASIVE PAD
2 - 3M ROLOCŸ BRISTLE DISC
3 - PLASTIC/WOOD SCRAPER
9 - 10 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

(12) Disconnect heater hoses from heater core and
remove hose assembly.
(13) Disconnect throttle and speed control cables.
(14) Remove upper radiator hose from engine.
(15) Remove lower radiator hose from engine.
(16) Remove radiator/cooling module assembly.
(17) Disconnect the engine to body ground straps
at the left side of cowl.
(18) Disconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(19) Remove coil over plugs.
(20) Release fuel rail pressure.
(21) Remove fuel rail and secure away from
engine.
NOTE: It is not necessary to release the quick con-
nect fitting from the fuel supply line for engine
removal.
(22) Remove the PCV hose.
(23) Remove the breather hoses.
(24) Remove the vacuum hose for the power brake
booster.
(25) Disconnect knock sensors.
(26) Remove engine oil dipstick tube.
(27) Remove intake manifold.
(28) Install engine lifting fixture,special tool#8247,
using original fasteners from the removed intake
manifold, and fuel rail. Torque to factory specifica-
tions.
NOTE: Recheck bolt torque for engine lift plate
before removing engine.
(29) Secure the left and right engine wiring har-
nesses away from engine.
(30) Raise vehicle.
(31) Disconnect oxygen sensor wiring.
(32) Disconnect crankshaft postion sensor.
(33) Disconnect the engine block heater power
cable, if equipped.
(34) Disconnect the front propshaft at the front
differential and secure out of way.
NOTE: It is necessary to disconnect the front prop-
shaft for access to the starter and left side exhaust
flange.(35) Remove the starter.
(36) Remove the ground straps from the left and
right side of the block.
(37) Disconnect the right and left exhaust pipes at
the manifolds and from the crossover, and remove
from the vehicle.
NOTE: The exhaust clamps at the manifolds cannot
be reused. New clamps must be used or leaks may
occur.
(38) Remove the structural cover.
(39) Remove torque convertor bolts, and mark
location for reassembly.
(40) Remove transmission bellhousing to engine
bolts.
(41) Remove left and right engine mount thru
bolts.
(42) Lower the vehicle.
(43) Support the transmission with a suitable jack.
(44) Connect a suitable engine hoist to the engine
lift plate.
(45) Remove engine from vehicle.
INSTALLATION
(1) Position the engine in the vehicle.
(2) Install both left and right side engine mounts
onto engine.
(3) Raise the vehicle.
(4) Install the transmission bellhousing to engine
mounting bolts. Tighten the bolts to 41 N´m (30ft.
lbs.).
(5) Tighten the engine mount thru bolts.
(6) Install the torque convertor bolts.
(7) Connect the ground straps on the left and right
side of the engine.
(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
NOTE: New clamps must be used on exhaust man-
ifold flanges. Failure to use new clamps may result
in exhaust leaks.
(12) Install the left and right exhaust pipes.
(13) Connect the left and right oxygen sensors.
(14) Lower vehicle.
(15) Remove the engine lift plate.
(16) Connect the knock sensors.
DRENGINE - 3.7L 9 - 11
ENGINE - 3.7L (Continued)

(17) Connect the engine to body ground straps at
the left side of the cowl.
(18) Install the intake manifold.
(19) Install the engine oil dipstick tube.
(20) Install the power brake booster vacuum hose.
(21) Install the breather hoses.
(22) Install the PCV hose.
(23) Install the fuel rail.
(24) Install the coil over plugs.
(25) Connect the engine wiring harness at the fol-
lowing points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(26) Reinstall the radiator/cooling module assem-
bly.
(27) Connect lower radiator hose.
(28) Connect upper radiator hose.
(29) Connect throttle and speed control cables.
(30) Install the heater hose assembly.
(31) Install coolant recovery bottle.
(32) Install the power steering pump.
(33) Install the generator.
(34) Install the A/C compressor.
(35) Install the drive belt.
(36) Install the fan shroud with the viscous fan
assembly.
(37) Install the radiator core support bracket.
(38) Install the air cleaner assembly.
(39) Refill the engine cooling system.
(40) Recharge the air conditioning.
(41) Install the hood.
(42) Check and fill engine oil.
(43) Connect the battery negative cable.
(44) Start the engine and check for leaks.SPECIFICATIONS
SPECIFICATIONS ± 3.7L ENGINE
DESCRIPTION SPECIFICATION
Engine Type 90É SOHC V-6 12-Valve
Displacement 3.7 Liters / 3700 cc
226 ( Cubic Inches)
Bore 93.0 mm (3.66 in.)
Stroke 90.8 mm (3.40 in.)
Compression Ratio 9.1:1
Horsepower 210 BHP @ 5200 RPM
Torque 225 LB-FT @ 4200 RPM
Lead Cylinder #1 Left Bank
Firing Order 1-6-5-4-3-2
CYLINDER BLOCK
Cylinder Block Cast Iron
Bore Diameter 93.0   .0075 mm
(3.6619   0.0003 in.)
Out of Round (MAX) 0.076 mm (0.003 in.)
Taper (MAX) 0.051 mm (0.002 in.)
PISTONS
Material Aluminum Alloy
Diameter 92.975 mm (3.6605 in.)
Weight 367.5 grams (12.96 oz)
Ring Groove Diameter
No. 1 83.73 - 83.13 mm
(3.296 - 3.273 in.)
No. 2 82.833 - 83.033 mm
(3.261 - 3.310 in.)
No. 3 83.88 - 84.08 mm
(3.302 - 3.310 in.)
PISTON PINS
Type Floating
Clearance In Piston 0.006 - 0.015 mm
(0.0002 - 0.0005 in.)
Diameter 24.017 - 24.020 mm
(0.9455 - 0.9456 in.)
PISTON RINGS
Ring Gap
Top Compression Ring 0.20 - 0.36 mm
(0.0079 - 0.0142 in.)
9 - 12 ENGINE - 3.7LDR
ENGINE - 3.7L (Continued)

(8) Starting at the outside working inward, loosen
the camshaft bearing cap retaining bolts 1/2 turn at
a time. Repeat until all load is off the bearing caps.
CAUTION: DO NOT STAMP OR STRIKE THE CAM-
SHAFT BEARING CAPS. SEVERE DAMAGE WILL
OCCUR TO THE BEARING CAPS.
NOTE: When the camshaft is removed the rocker
arms may slide downward, mark the rocker arms
before removing camshaft.
(9) Remove the camshaft bearing caps and the
camshaft.
INSTALLATION
(1) Lubricate camshaft journals with clean engine
oil.
NOTE: Position the right side camshaft so that the
camshaft sprocket dowel is near the 10 o'clock
position, This will place the camshaft at the neutral
position easing the installation of the camshaft
bearing caps.
(2) Position the camshaft into the cylinder head.
(3) Install the camshaft bearing caps, hand tighten
the retaining bolts.
NOTE: Caps should be installed so that the
stamped numbers on the caps are in numerical
order, ( 1 thru 4 ) from the front to the rear of the
engine. All caps should be installed so that the
stamped arrows on the caps point toward the front
of the engine.
(4) Working in 1/2 turn increments, tighten the
bearing cap retaining bolts starting with the middle
cap working outward (Fig. 27).
(5) Torque the camshaft bearing cap retaining
bolts to 11 N´m (100 in. lbs.).
(6) Position the camshaft drive gear into the tim-
ing chain aligning the V6 mark between the two
marked chain links (Two links marked during remov-
al).
(7) Using Special Tool 8428 Camshaft Wrench,
rotate the camshaft until the camshaft sprocket
dowel is aligned with the slot in the camshaft
sprocket. Install the sprocket onto the camshaft.
CAUTION: Remove excess oil from camshaft
sprocket bolt. Failure to do so can cause bolt over-
torque resulting in bolt failure.
(8) Remove excess oil from camshaft sprocket bolt,
then install the camshaft sprocket retaining bolt and
hand tighten.(9) Remove timing chain wedge special tool 8379.
(10) Using Special Tool 6958 spanner wrench with
adapter pins 8346, torque the camshaft sprocket
retaining bolt to 122 N´m (90 ft. lbs.).
(11) Install the camshaft position sensor.
(12) Install the cylinder head cover(Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
CYLINDER HEAD COVER(S)
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove air cleaner assembly, resonator assem-
bly and air inlet hose.
(3) Drain cooling system, below the level of the
heater hoses(Refer to 7 - COOLING - STANDARD
PROCEDURE).
(4) Remove accessory drive belt(Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - REMOV-
AL).
(5) Remove air conditioning compressor retaining
bolts and move compressor to the left.
(6) Remove heater hoses.
(7) Disconnect injector and ignition coil connectors.
(8) Disconnect and remove positive crankcase ven-
tilation (PCV) hose.
(9) Remove oil fill tube.
(10) Un-clip injector and ignition coil harness and
move away from cylinder head cover.
(11) Remove right rear breather tube and filter
assembly.
Fig. 27 CAMSHAFT BEARING CAPS TIGHTENING
DRENGINE - 3.7L 9 - 35
CAMSHAFT(S) (Continued)