1999 DODGE RAM cooling

Terminal burned, affecting
performance ............ A ........... (1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Vibration ............... 1 ............ Suggest replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Check fan motor/controls. Inoperative includes
intermittent operation or out of OEM specification.









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WATER PUMPS (NON-ELECTRIC)
WATER PUMP (NON-ELECTRIC) INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
corroded ............... A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Corrosion (internal) is
excessive, affecting
performance ............ A ............ Require replacement.
Corrosion (internal) is
excessive, not affecting
performance ............ 2 . Suggest cooling system service.
Inoperative ............. A ........ ( 1) Require replacement.
Leaking ................. A ............ Require replacement.
Noisy ................... A ............ Require replacement.
Rotation incorrect for
application ............ B .. Require repair or replacement.
Shaft bent .............. A ............ Require replacement.
( 1) - Inoperative includes intermittent operation or out of
OEM specification.









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WIRING HARNESSES AND CONNECTORS

GEN ER AL C O OLIN G S YSTE M S ER VIC IN G
1999 D odge P ic ku p R 1500
GENERAL INFORMATION
General Cooling System Servicing
* PLEASE READ THIS FIRST *
The following article is for general information only.
Information may not apply to all years, makes and models. See specific
article in the ENGINE COOLING section.
DESCRIPTION
The basic liquid cooling system consists of a radiator, water
pump, thermostat, electric or belt-driven cooling fan, pressure cap,
heater, and various connecting hoses and cooling passages in the block
and cylinder head.
MAINTENANCE
DRAINING
Remove radiator cap and open heater control valve to maximum
heat position. Open drain cocks or remove plugs in bottom of radiator
and engine block. In-line engines usually have one plug or drain cock,
while "V" type engines will have 2, one in each bank of cylinders.
CLEANING
A good cleaning compound removes most rust and scale. Follow
manufacturer's instructions in the use of cleaner. If considerable
rust and scale has to be removed, cooling system should be flushed.
Clean radiator air passages with compressed air.
FLUSHING
CAUTION: Some manufacturers use an aluminum and plastic radiator.
Flushing solution must be compatible with aluminum.
Back Flushing
Back flushing is an effective means of removing cooling
system rust and scale. The radiator, engine and heater core should be
flushed separately.
Radiator
To flush radiator, connect flushing gun to water outlet of
radiator and disconnect water inlet hose. To prevent flooding engine,
use a hose connected to radiator inlet. Use air in short bursts to
prevent damage to radiator. Continue flushing until water runs clear.
Engine
To flush engine, remove thermostat and replace housing.
Connect flushing gun to water outlet of engine. Flush using short air
bursts until water runs clean.
Heater Core
Flush heater core as described for radiator. Ensure heater
control valve is set to maximum heat position before flushing heater.

REFILLING
To prevent air from being trapped in engine block, engine
should be running when refilling cooling system. After system is full,
continue running engine until thermostat is open, then recheck fill
level. Do not overfill system.
TESTING
THERMOSTAT
1) Visually inspect thermostat for corrosion and proper
sealing of valve and seat. If okay, suspend thermostat and thermometer
in a 50/50 mixture of coolant and water. See Fig. 1. Do not allow
thermostat or thermometer to touch bottom of container. Heat water
until thermostat just begins to open.
2) Read temperature on thermometer. This is the initial
opening temperature and should be within specification. Continue
heating water until thermostat is fully open and note temperature.
This is the fully opened temperature. If either reading is not to
specification, replace thermostat.
Fig. 1: Testing Thermostat in Anti-Freeze/Water Solution
PRESSURE TESTING
A pressure tester is used to check both radiator cap and

complete cooling system. Test components as follows, following tool
manufacturer's instructions.
Radiator Cap
Visually inspect radiator cap, then dip cap into water and
connect to tester. Pump tester to bring pressure to upper limit of cap
specification. If cap fails to hold pressure, replace cap.
Fig. 2: Testing Radiator Pressure Cap
Cooling System
1) With engine off, wipe radiator filler neck seat clean.
Fill radiator to correct level. Attach tester to radiator and pump
until pressure is at upper level of radiator rating.
2) If pressure drops, inspect for external leaks. If no leaks
are apparent, detach tester and run engine until normal operating
temperature is reached. Reattach tester and observe. If pressure
builds up immediately, a possible leak exists from a faulty head
gasket or crack in head or block.
NOTE: Pressure may build up quickly. Release any excess pressure
or cooling system damage may result.
3) If there is no immediate pressure build up, pump tester to
within system pressure range (on radiator cap). Vibration of gauge
pointer indicates compression or combustion leak into cooling system.
Isolate leak by shorting each spark plug wire to cylinder block. Gauge
pointer should stop or decrease vibration when leaking cylinder is
shorted.

pointer is at one o'clock position. Push in on knob slightly and
continue rotating knob to its full clockwise stop. Place knob pointer
at a position about .32" (8 mm) beyond end of Red stripe. Release
knob. If knob is pointing at about .32" (8 mm) beyond end of Red
stripe, go to next step. If knob is not pointing at about .32" (8 mm)
beyond end of Red stripe, go back to step 2) and repeat adjustment
procedure.
4) Rotate temperature control knob counterclockwise so that
knob pointer is at 12 o'clock position. Push temperature control knob
straight into heater control panel until perimeter of knob (not knob
pointer) is flush with base of heater control panel.
5) Rotate temperature control knob to its full clockwise
stop. Release knob. Knob pointer should be aimed at end of Red stripe.
If knob is pointed at end of Red stripe, go to next step. If knob is
not pointed at end of Red stripe, go back to step 2) and repeat
adjustment procedure.
6) Rotate temperature control knob to its full
counterclockwise stop. Release knob. If knob springs back, self-
adjuster clip securing temperature control cable to blend-air door
lever is improperly installed. See TEMPERATURE CONTROL CABLE R & I
under REMOVAL & INSTALLATION. If knob does not springs back,
temperature control cable adjustment is complete.
TROUBLE SHOOTING
HEATER PERFORMANCE
Check cooling system. Check serpentine drive belt tension.
Check radiator and radiator fan operation. Ensure that accessory
vacuum supply line is connected at power brake booster (Dakota) or
engine vacuum source (except Dakota).
TESTING
WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all SERVICE PRECAUTIONS and DISABLING &
ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY
article.
BLOWER MOTOR RELAYS
1) Blower motor relay is located in Power Distribution Center
(PDC). On Ram Van/Wagon, high speed blower motor relay is located in
engine compartment (on side of heater assembly). On all models,
disconnect negative battery cable. Remove blower motor relay. Using an
ohmmeter, check for continuity between terminals No. 87A and 30 of
relay. See Fig. 1. If continuity does not exist, replace relay. If
continuity exists, go to next step.
2) Using an ohmmeter, check for continuity between terminals
No. 30 and 87 of relay. If continuity exists, replace relay. If
continuity does not exist, go to next step.
3) Measure resistance between terminals No. 85 and 86 of
relay. Reading should be 70-80 ohms. If reading is not as specified,
replace relay. If reading is as specified, go to next step.
4) Using jumper wires, connect battery voltage to terminal
No. 86 and ground terminal No. 85. See Fig. 1. Check that continuity
exists between terminals No. 30 and 87. Check that continuity does not
exist between terminals No. 87A and 30. If continuity is not as
specified, replace blower motor relay. If continuity is as specified,
relay is okay.

1) Connect a vacuum gauge in line with Black heater vacuum
supply hose (located at tee near power brake booster, in engine
compartment). Position gauge so it can be viewed from passenger
compartment.
2) Start engine. While observing vacuum gauge, rotate mode
control knob to each mode position (one position at a time). Pause
after each selection. Vacuum gauge should drop then return to 8 in. Hg
shortly after each selection is made. If vacuum gauge reading is as
specified, go to next step. If gauge reading is not as specified,
check for vacuum leak in vacuum lines or heater control panel.
3) Move temperature control knob quickly to full hot and full
cold positions. A distinct sound of blend-air door hitting its stops
should be heard. No spring-back of knob should exist.
4) If temperature control knob operates as specified,
temperature control system is okay. If temperature control knob does
not operate as specified, check condition, routing, installation and
adjustment of temperature control cable. See
TEMPERATURE CONTROL CABLE ADJUSTMENT.
HEATER OUTPUT
1) Start engine. Allow engine to reach normal operating
temperature. With engine at idle, set controls to maximum heat, floor
and high blower positions. Using a thermometer, check air temperature
coming from floor vents. See HEATER OUTPUT TEMPERATURE table.
2) If floor outlet air temperature is lower than specified,
check cooling system and electric cooling fan. See ELECTRIC COOLING
FAN article.
3) Check that both return and supply heater hoses are hot. If
coolant return hose is much cooler than supply hose, repair coolant
obstruction in heater system. Check for air flow obstruction in heater
system. Check blend air door for proper operation.
HEATER OUTPUT TEMPERATURE









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Ambient Temp. F (C) Outlet Vent Temp. F (C)
Except Durango
60 (15.6) ............................................. 144 (62.2\
)
70 (21.1) ............................................. 147 (63.8\
)
80 (26.6) ............................................. 150 (65.5\
)
90 (32.2) ............................................. 153 (67.2\
)
Durango
60 (15.6) ............................................. 126 (52.2\
)
70 (21.1) ............................................. 133 (56.1\
)
80 (26.6) ............................................. 139 (59.4\
)
90 (32.2) ............................................. 144 (62.2\
)









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REMOVAL & INSTALLATION
* PLEASE READ THIS FIRST *
WARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all SERVICE PRECAUTIONS and DISABLING &
ACTIVATING AIR BAG SYSTEM procedures in AIR BAG SYSTEM SAFETY
article.
BLEND AIR DOOR MOTOR
Removal & Installation (Ram Pickup)
Remove heater assembly. See HEATER ASSEMBLY. Remove blend air

door servo motor electrical connector and mounting bolts. Remove blend
air door servo motor. Ensure blend air door operates properly without
restriction or binding. To install, reverse removal procedure.
Removal & Installation (Ram Van/Wagon)
Disconnect negative battery cable. Remove glove box.
Disconnect wire harness connector from blend air door motor.
Disconnect blend air door motor lever and remove link from retainer.
Remove 3 mounting bolts and remove blend air door motor.
BLOWER MOTOR
Removal (Dakota & Durango)
1) Disconnect negative battery cable. Remove and disassemble
heater assembly. See HEATER ASSEMBLY. Disconnect blower motor lead at
bottom of housing. Remove 6 bolts and blower motor housing cover.
2) Remove blower motor and fan assembly. Place reference
marks on blower motor and fan for installation reference. Remove
blower fan retainer clip. Pull blower motor fan off blower motor
shaft.
Installation
Align reference marks made during removal. Press blower fan
hub onto blower motor shaft. Ensure retainer clip ears are indexed
over flats of blower motor shaft and fan hub. To complete
installation, reverse removal procedure.
Removal (Ram Pickup)
1) Blower motor is located under glove box and can be removed
from passenger compartment. See Fig. 5. Disconnect negative battery
cable. Disconnect blower motor cooling tube. Remove blower motor
electrical connector from retainer. Disconnect electrical connector.
2) Remove blower motor and fan assembly mounting bolts.
Remove blower motor and fan assembly. Place reference marks on blower
motor and fan for installation reference. Remove blower motor fan
retainer clip. Pull blower motor fan off blower motor shaft.
Installation
Align reference marks made during removal. Press blower fan
hub onto blower motor shaft. Ensure retainer clip ears are indexed
over flats of blower motor shaft and fan hub. Ensure blower motor seal
is installed on housing. To complete installation, reverse removal
procedure.
Removal (Ram Van/Wagon)
1) Disconnect negative battery cable. Remove top half of
radiator shroud. At right side of engine compartment, disconnect
blower motor wiring connector and motor cooling tube. Remove nuts and
washers from blower motor backing plate to heater housing studs. See
Fig. 6 .
2) Remove blower motor assembly. Place reference marks on
blower motor and fan for installation reference. Remove blower motor
fan retainer clip. Pull blower motor fan off blower motor shaft.
Inspect backing plate seal for breaks and adhesion.
Installation
Align reference marks made during removal. Press blower fan
hub onto blower motor shaft. Ensure retainer clip ears are indexed
over flats of blower motor shaft and fan hub. Apply a small bead of
rubber sealant to blower motor side of rubber seal. To complete
installation, reverse removal procedure.

removal procedure.
HEATER ASSEMBLY
Removal (Dakota & Durango)
1) Disconnect negative battery cable. Drain cooling system.
Remove instrument panel. See INSTRUMENT PANEL.
2) In engine compartment, disconnect heater hoses and plug
all openings. Remove 4 heater assembly nuts from engine compartment
firewall. Inside vehicle, remove heater assembly support brace screw,
and swing support brace out of way. Move passenger seat rearward.
3) Carefully pull heater assembly rearward until studs and
heater core tubes clear firewall. Lower heater assembly and rotate
assembly until studs are facing downward. Remove heater assembly from
vehicle.
4) Place heater assembly on work bench with assembly housing
cover facing down. Remove 2 bolts securing heater assembly housing
cover to blower motor housing cover. Unplug vacuum harness connector
from panel/defrost door actuator.
5) Remove floor duct from heater assembly housing. Remove 2
bolts securing heater assembly housing cover to lower housing near
floor outlet. Turn assembly over. Disengage vacuum harness retainer
and vacuum harness. Remove 13 screws securing housing cover.
6) Remove blend-air door lever. Gently pry panel-defrost door
lever off. Pull up on heater assembly housing cover far enough to
separate cover sealant and remove cover.
Installation
Ensure blower motor housing cover sealant is in place and in
good condition. To complete installation, reverse removal procedure.
Removal (Ram Pickup)
1) Disconnect negative battery cable. Drain cooling system.
In engine compartment, remove coolant hoses from heater core tubes.
Plug all openings. Remove coolant overflow bottle. Remove instrument
panel. See INSTRUMENT PANEL . Remove Powertrain Control Module (PCM)
and position aside. DO NOT disconnect 60-pin connector from PCM.
2) Remove attaching nuts from studs on engine compartment
side of dash panel. Remove defrost duct. Disconnect electrical
connectors. Remove attaching nuts from studs in passenger compartment
side of dash panel. Remove heater assembly from vehicle.
3) Place heater assembly upside-down on work bench. Remove
screw securing floor duct to bottom of heater assembly and slide floor
duct off of center heat duct adapter. Unsnap center heat duct adapter
from bottom of heater assembly housing. Remove screw hidden behind
adapter. Remove remaining screws and separate heater assembly.
Installation
Ensure mode door pivot pins are properly inserted in holes.
To complete installation, reverse removal procedure.
Removal & Installation (Ram Van/Wagon)
1) Disconnect negative battery cable. Drain engine cooling
system. In engine compartment, protect generator from coolant
spillage. Remove heater hoses from heater core tubes. Plug all
openings. Remove grille, cowl grille support panel, right headlight
assembly, and right radiator core support assembly. See Fig. 7.
2) From inside vehicle, remove glove box bin. Through glove
box opening and from under instrument panel, remove nuts and bolts
attaching heater assembly to dash panel.
3) Remove blower housing flange screws. Separate heater
assembly from blower housing. See Fig. 6. Carefully remove heater
assembly from vehicle.