1999 DODGE RAM Service Repair Manual

Fig. 1: Identifying Blower Motor Relay Terminals
Courtesy of Chrysler Corp.
BLOWER MOTOR RESISTOR
1) Disconnect negative battery cable. Disconnect blower motor
resistor harness connector. Using an ohmmeter, check for continuity
between all blower motor resistor terminals. If continuity exists
between all terminals, go to next step. If continuity does not exist
between all terminals, replace faulty blower motor resistor.
2) Check for open or short in circuits between blower motor
resistor and heater control panel. Also check for open or short in
wire between blower motor resistor and blower motor.
BLOWER MOTOR SWITCH
Dakota, Durango & Ram Pickup
1) Using a voltmeter, check for battery voltage at underhood
power distribution center fuse No. 5 (40-amp) on Dakota and Durango;
fuse No. 12 (40-amp) on Ram Pickup. If battery voltage exists, go to
next step. If battery voltage does not exist, check for open in Red
wire between battery and underhood power distribution center. If Red
wire is okay, replace underhood power distribution center.
2) Disconnect negative battery cable. Remove heater control
panel. See HEATER CONTROL PANEL R & I . Disconnect heater control panel
harness connector. Using an ohmmeter, check for continuity between
heater control panel harness connector terminal No. 7 (Black wire on
Dakota and Durango; Black/Orange on Ram Pickup) and ground. If
continuity exists, go to step 4).
3) If continuity does not exist, repair open in Black wire or
Black/Orange wire between heater control panel harness connector
terminal No. 7 and ground connector located at lower right corner of
instrument panel (Dakota and Durango) or behind center of instrument
panel (Ram Pickup).
4) Place heater mode control knob to any position except OFF.

Using an ohmmeter, check for continuity between heater control panel
connector terminal No. 7 and terminals No. 3, 4, 5 and 6 while
rotating blower motor switch. See Fig. 2.
5) If continuity does not exist at any terminal, replace
faulty heater control panel. If continuity exists as specified, check
for open in circuits between heater control panel and blower motor
resistor. Also check for an open in circuit between heater control
panel and blower motor.
Fig. 2: Identifying Blower Motor Switch Connector Terminals (Dakota,
Durango & Ram Pickup)
Courtesy of Chrysler Corp.
Ram Van/Wagon
1) Disconnect negative battery cable. Remove heater control
panel. See HEATER CONTROL PANEL R & I . Disconnect heater control panel
harness connector. Using an ohmmeter, check for continuity between
heater control panel C3 harness connector terminal "C" (Black wire)
and ground. See Fig. 4. Go to next step.
2) If continuity exists, go to next step. If continuity does
not exist, repair open in Black wire between heater control panel and
ground connector located at lower right of steering column.
3) Place heater mode control knob to any position except OFF.
Using an ohmmeter, check for continuity between heater control panel
C3 connector terminals "B" (Violet wire) and "C" (Black wire). If
continuity exists, go to next step. If continuity does not exist,
replace faulty heater control panel.
4) Using an ohmmeter, check for continuity between heater
control panel C3 connector terminal "B" (Violet wire) and C1 connector\
terminal "E" (Violet wire). See Fig. 3. If continuity exists, go to
next step. If continuity does not exist, repair open in Violet wire
between heater control panel C3 and C1 connectors.
5) Using an ohmmeter, check for continuity between heater
control panel C1 connector terminal "E" and terminals "B", "C" and "D"
while rotating blower motor switch. See Fig. 3.
6) If continuity does not exist at any terminal, replace
faulty heater control panel. If continuity exists as specified, check

for open in circuits between heater control panel and blower motor
resistor. Also check for an open in circuit between heater control
panel connector and blower motor relay.
Fig. 3: Identifying Heater Control Panel C1 Connector Terminals
Courtesy of Chrysler Corp.
Fig. 4: Identifying Heater Control Panel C3 Connector Terminals
Courtesy of Chrysler Corp.
HEATER CONTROL PANEL

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.

Fig. 5: Identifying Heater Assembly Components (Ram Pickup)
Courtesy of Chrysler Corp.

Fig. 6: Identifying Heater Assembly Components (Ram Van/Wagon)
Courtesy of Chrysler Corp.
BLOWER MOTOR RESISTOR
Removal & Installation (Dakota & Durango)
Blower motor resistor is located in engine compartment, under
upper right corner of dash panel. Disconnect negative battery cable.
Remove cowl plenum cover to access resistor. Remove blower motor
resistor connector. Remove resistor retaining bolts. Remove blower
motor resistor. To install, reverse removal procedure.
Removal & Installation (Ram Pickup)
Blower motor resistor is located under glove box, attached to
blower motor housing. See Fig. 5. Disconnect negative battery cable.
Remove blower motor resistor connector. Remove resistor retaining
bolts. Remove blower motor resistor. To install, reverse removal
procedure.
Removal & Installation (Ram Van/Wagon)
Blower motor resistor is located behind glove box, attached
to dash plenum panel. Disconnect negative battery cable. Remove glove
box bin. Disconnect blower motor resistor connector. Remove resistor
retaining bolts. Remove blower motor resistor. To install, reverse

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.