1999 DODGE RAM instrument panel

"G" ABBREVIATION TABLE

"G" ABBREVIATION TABLE
ABBREVIATION DEFINITION G grams GND or GRND Ground GRN Green GRY Gray Ga. Gauge Gals. gallons Gov. Governor

"H" ABBREVIATION TABLE

"H" ABBREVIATION TABLE
ABBREVIATION DEFINITION H/D Heavy Duty HAC High Altitude Compensation HC Hydrocarbons HEDF High Speed Electro Drive Fan relay or
circuit HEGO Heated Exhaust Gas Oxygen Sensor HEGOG or HEGO Ground circuit HEI High Energy Ignition HLDT Headlight HO High Output HP High Performance HSC High Swirl Combustion HSO High Specific Output HTR Heater HVAC Heating Headlt. Headlight Hg Mercury Hgt. Height Htr. Heater Hz Hertz (Cycles Per Second)

"I" ABBREVIATION TABLE

"I" ABBREVIATION TABLE
ABBREVIATION DEFINITION I.D. Inside Diameter IAC Idle Air Control IACV Idle Air Control Valve IC Integrated Circuit ID Identification IDM Ignition Diagnostic Monitor IGN Ignition system or circuit ILC Idle Load Compensator In. Hg Inches of Mercury INCH Lbs. Inch Pounds INFL REST Inflatable Restraint INJ Injector or Injection IP Instrument Panel IPC Instrument Panel Cluster

BLOWER MOTOR VIBRATION
Possible causes of blower motor vibration include:
* Improper blower motor mounting.
* Improper blower wheel or fan mounting.
* Blower wheel or fan out of balance.
* Blower motor faulty.
BLOWER MOTOR NOISE
Possible causes of blower motor noise include:
* Foreign material in blower motor housing.
* Foreign material in A/C-heater housing.
* Improper blower motor mounting.
* Improper blower wheel or fan mounting.
* Blower motor faulty.
VACUUM CONTROL SYSTEM DIAGNOSIS
VACUUM CONTROL ONE-WAY CHECK VALVE
NOTE: Some models use brake booster check valve for vacuum source.
These models do not use another in-line vacuum check valve.
1) In engine compartment, locate Black vacuum hose that runs
from brake booster check valve or intake manifold, through firewall
near heater hoses or expansion valve. This supply vacuum hose goes to
A/C-heater control panel vacuum switch.
2) Within Black vacuum hose, disconnect and remove check
valve near intake manifold or brake booster. Connect vacuum gauge to
an external vacuum pump. Start vacuum pump. Plug end of hose probe on
vacuum gauge. Adjust bleed valve on vacuum gauge to obtain an exact
vacuum reading of 8 in. Hg.
3) Unplug and plug end of hose probe on vacuum gauge several
times to ensure exact vacuum reading. Connect vacuum gauge hose probe
to control panel side of check valve. Vacuum gauge reading should be 8
in. Hg. Replace check valve if vacuum leak exists.
4) Connect vacuum gauge hose probe to engine side of check
valve. Vacuum should flow through check valve. Replace check valve if
operation is not as described.
VACUUM CONTROLS
1) This test checks for proper function of control panel
vacuum circuits. Perform steps 1) through 4) under VACUUM CONTROL ONE-\
WAY CHECK VALVE.
2) Connect vacuum gauge hose probe to Black vacuum hose end
that leads to A/C-heater control panel switch. Position vacuum gauge
so gauge reading can be observed from inside vehicle.
3) Operate A/C-heater controls (sliding lever or push
buttons) in all mode positions (floor, defrost, panel, etc.). Pause
after each selection to allow vacuum actuators or motors to energize
and stabilize. Record vacuum gauge reading at each selection.
4) After each selection, vacuum reading should be 7.5-8 in.
Hg. Maximum vacuum reading drop is .75 in. Hg. If proper vacuum
reading cannot be obtained, vacuum leak exists in selected circuit.
5) To check for vacuum leak(s), disconnect 7-way A/C-heater
control panel vacuum harness connector. See Fig. 1. If necessary,
remove control panel from instrument panel to access A/C-heater
control panel vacuum harness connector, or remove lower instrument

A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS (RAM PICKUP)








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Ambient Temp. High Side Low SideF (C) psi (kg/cm) psi (kg/cm)
70 (21) .............. 135-145 (9.5-10.2) ........ 35-40 (2.5-2\
.8)
80 (27) .............. 175-215 (12.3-15.1) ....... 40-50 (2.8-3\
.5)
90 (32) .............. 215-270 (15.1-19.0) ....... 50-60 (3.5-4\
.2)
100 (38) ............. 270-330 (19.0-23.2) ....... 60-70 (4.2-4\
.9)
110 (43) ............. 340-370 (23.9-26.0) ....... 70-80 (4.9-5\
.6)
120 (49) ............. 400-430 (28.1-30.2) ....... 85-90 (6.0-6\
.3)









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BLOWER MOTOR RELAY, HIGH SPEED BLOWER MOTOR RELAY &
COMPRESSOR CLUTCH RELAY
NOTE: Relays appear different, but testing procedures for blower
motor, high speed blower motor, and compressor clutch relays
are identical.
1) Front blower motor relay and compressor clutch relay are
located in Power Distribution Center (PDC). On Durango, high speed
blower motor relay is located in fuse/relay block under left side of
instrument panel.
2) Disconnect negative battery cable. Remove blower motor or
compressor clutch relay. Using an ohmmeter, check for continuity
between terminals No. 87A and 30 of relay. See Fig. 1 or 2. If
continuity does not exist, replace relay. If continuity exists, go to
next step.
3) 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.
4) 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.
5) Using jumper wires, connect battery voltage to terminal
No. 86 and ground terminal No. 85. See Fig. 1 or 2. 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 relay. If continuity is as
specified, relay is okay.
Fig. 1: Identifying Blower Motor Relay Terminals (Typical)
Courtesy of Chrysler Corp.

Fig. 2: Identifying Compressor Clutch Relay Terminals (Typical)
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 4 front blower motor resistor terminals, or 3 rear blower
motor resistor terminals. If continuity exists, go to next step. If
continuity does not exist, replace faulty blower motor resistor.
2) Check for open or short in circuits between blower motor
resistor and A/C-heater control panel. Also check for open or short in
wire between blower motor resistor and blower motor.
BLOWER MOTOR SWITCH
Front
1) Using a voltmeter, check underhood power distribution
center for battery voltage at fuse No. 5 (40-amp) on Dakota and
Durango, or fuse No. 5 (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 A/C-heater
control panel. See A/C-HEATER CONTROL PANEL R & I . Disconnect A/C-
heater control panel harness connector. Using an ohmmeter, check for
continuity between A/C-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 or
Black/Orange wire between A/C-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 mode control knob to any position except OFF. Using
an ohmmeter, check for continuity between A/C-heater control panel
connector terminal No. 7 and terminals No. 3, 4, 5, and 6 while
rotating blower motor switch. See Fig. 3.
5) If continuity does not exist at any terminal, replace
faulty A/C-heater control panel. If continuity exists as specified,
check for open in circuits between A/C-heater control panel and blower
motor resistor. Also check for an open in circuit between A/C-heater

controls to A/C. Start and operate engine at idle speed.
3) Using an ohmmeter, check for continuity between switch
terminals. Continuity should exist when suction pressure reading is
above 38 psi (2.7 kg/cm
) on Dakota; 43 psi (3.0 kg/cm) on Ram
Pickup. Continuity should not exist when suction pressure reading
drops below 20.5 psi (1.4 kg/cm
) on Dakota; 25 psi (1.8 kg/cm) on
Ram Pickup. If switch is okay, test and repair clutch control circuit
as needed. If switch is not okay, replace faulty clutch cycling
pressure switch.
ELECTRONIC CYCLING CLUTCH SWITCH
Durango
1) Locate electronic cycling clutch switch on thermal
expansion valve in engine compartment. Ensure system pressure is
correct. See A/C SYSTEM PERFORMANCE test. Ensure low pressure cut-out
switch and high pressure cut-out switch are working properly. See
LOW PRESSURE CUT-OUT SWITCH TEST and HIGH PRESSURE CUT-OUT SWITCH
test.
2) Disconnect negative battery cable. Disconnect electronic
cycling clutch switch and high pressure cut-out switch connectors.
Using an ohmmeter, check for continuity in Light Green/White wire
between electronic cycling clutch switch and high pressure cut-out
switch. If continuity exists in Light Green/White wire, go to next
step. If continuity does not exist in Light Green/White wire, repair
wire as necessary.
3) Disconnect low pressure cut-out switch connector. Using an
ohmmeter, check for continuity in Dark Blue/Yellow wire between
electronic cycling clutch switch and low pressure cut-out switch. If
continuity exists in Dark Blue/Yellow wire, go to next step. If
continuity does not exist in Dark Blue/Yellow wire, repair wire as
necessary.
4) Connect low pressure cut-out switch and high pressure cut-
out switch connectors. Connect negative battery cable. Turn ignition
on. Using voltmeter, check for battery voltage at electronic cycling
clutch switch connector terminal No. 2 (White wire). If battery
voltage exists, go to step 6).
5) If battery voltage does not exist, check fuse No. 7 (15-
amp) at junction block located at bottom left of instrument panel. If
fuse is okay, check for short or open in White wire between electronic
cycling clutch switch connector and fuse No. 7 (15-amp) at junction
block.
6) Connect electronic cycling clutch switch connector. Ensure
ambient temperature is between 68-90
F (20-30C). Start engine and
turn A/C on. If compressor clutch cycles 2-3 times per minute, replace
faulty electronic cycling clutch switch. If compressor clutch does not
cycle, check PCM for proper operation. See appropriate G - TESTS
W/CODES article in ENGINE PERFORMANCE section.
HIGH PRESSURE CUT-OUT SWITCH
1) Locate high pressure cut-out switch on compressor
discharge line, near compressor. Ensure system pressure is correct.
See A/C SYSTEM PERFORMANCE test. Disconnect negative battery cable.
Disconnect high pressure cut-off switch connector.
2) Using an ohmmeter, check for continuity between switch
terminals. If continuity exists, test and repair clutch control
circuit as needed. If continuity does not exist, replace faulty
switch.
LOW PRESSURE CUT-OUT SWITCH TEST
Durango

1) Locate low pressure cut-out switch located on suction
line, near firewall. Ensure system pressure is correct. See
A/C SYSTEM PERFORMANCE test. Disconnect negative battery cable.
Disconnect low pressure cut-out switch connector.
2) Place a jumper wire across terminals of low pressure cut-
out switch harness connector. Connect negative battery cable. Connect
manifold gauge set. Set A/C-heater controls to A/C. Start and operate
engine at idle speed.
3) Using an ohmmeter, check for continuity between switch
terminals. Continuity should exist when suction pressure reading is
between 13-27 psi (.9-1.9 kg/cm
). Continuity should not exist when
suction pressure reading is 10 psi (.7 kg/cm) or lower. If switch is
okay, repair open or short in Brown wire between low pressure cut-out
switch and PCM. If switch is not okay, replace faulty low pressure
cut-out switch.
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.
A/C-HEATER ASSEMBLY
Removal (Dakota & Durango - Front)
1) Disconnect negative battery cable. Drain cooling system.
Discharge A/C system, using approved refrigerant recovery/recycling
equipment. Disconnect refrigerant lines from evaporator and plug or
cover all openings in A/C system. Remove instrument panel. See
INSTRUMENT PANEL .
2) In engine compartment, disconnect heater hoses. Remove 4
A/C-heater assembly nuts from engine compartment firewall. Inside
vehicle, remove A/C-heater assembly support brace screw, and swing
support brace out of way. Move passenger seat rearward.
3) Carefully pull A/C-heater assembly rearward until studs
and heater core tubes clear firewall. Lower A/C-heater assembly and
rotate assembly until studs are facing downward. Remove A/C-heater
assembly from vehicle. See Fig. 4.
4) Place A/C-heater assembly on work bench with assembly
housing cover facing down. Remove 2 screws securing A/C-heater
assembly housing cover to blower motor housing cover. Unplug vacuum
harness connector from panel/defrost door actuator.
5) Remove floor duct from A/C-heater assembly housing. Remove
2 screws securing A/C-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 A/C-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.

assembly towards right side of vehicle and remove rear A/C-heater
assembly.
5) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS .
Removal (Ram Pickup - Front)
1) Disconnect negative battery cable. Drain cooling system.
In engine compartment, remove coolant hoses from heater core tubes.
Remove coolant overflow bottle.
2) Discharge A/C system, using approved refrigerant
recovery/recycling equipment. Disconnect refrigerant lines from
evaporator and plug or cover all openings in A/C system. Remove
instrument panel. See INSTRUMENT PANEL. Remove Powertrain Control
Module (PCM) and position aside. DO NOT disconnect 60-pin connector
from PCM.
3) 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 A/C-heater assembly from vehicle. See
Fig. 5 .
4) Place A/C-heater assembly upside-down on work bench.
Remove screw securing floor duct to bottom of A/C-heater assembly and
slide floor duct off of center heat duct adapter. Unsnap center heat
duct adapter from bottom of A/C-heater assembly housing. Remove screw
hidden behind adapter. Remove remaining screws and separate A/C-heater
assembly.
Installation
Ensure mode door pivot pins are properly inserted in holes.
To complete installation, reverse removal procedure.
A/C-HEATER CONTROL PANEL R & I
Removal & Installation (Dakota & Durango)
1) Disconnect negative battery cable. On models equipped with
A/T, unlock ignition switch. Set parking brake and place gear selector
lever in "L" position. If equipped, set tilt steering column in lowest
position.
2) On all models, carefully pry bezel away from instrument
panel to disengage clips. Unplug connectors from cigarette lighter and
auxiliary power outlet. Disconnect fog light switch (if equipped).
Remove A/C-heater control panel screws.
3) Pull control panel outward enough to disconnect wiring
connector, vacuum harness, and temperature control cable. Remove A/C-
heater control panel. To install, reverse removal procedure. Adjust
temperature control cable. See TEMPERATURE CONTROL CABLE ADJUSTMENT .
Removal & Installation (Ram Pickup)
1) Disconnect negative battery cable. Reach under driver's
side of instrument panel, near transmission tunnel and unplug A/C-
heater control panel to A/C-heater assembly vacuum harness connector.
Disconnect vacuum harness from center air duct.
2) On models equipped with A/T, unlock ignition switch. Set
parking brake and place gear selector lever in "L" position. If
equipped, set tilt steering column in lowest position.
3) On all models, remove screw securing cluster bezel to
instrument panel. See Fig. 6. Carefully pry bezel away from instrument
panel to disengage clips. Unplug connectors from cigarette lighter and
auxiliary power outlet.
4) Remove 4 screws attaching A/C-heater control panel. Pull
control panel outward enough to disconnect wiring connector, vacuum
harness and temperature control cable. Remove A/C-heater control

install, reverse removal procedure.
Removal & Installation (Ram Pickup - Front)
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
screws. Remove blower motor resistor. To install, reverse removal
procedure.
BLOWER MOTOR SWITCH (REAR)
Removal & Installation (Durango)
Disconnect negative battery cable. Pry above indentations at
outer perimeter of rear blower motor switch. Pull rear blower motor
switch and disconnect electrical connector. Remove rear blower motor
switch. To install, reverse removal procedure.
COMPRESSOR
Removal & Installation
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
refrigerant lines and plug or cover all openings in A/C system.
2) Remove drive belt. Disconnect compressor electrical leads.
Remove compressor mounting nuts and bolts. Remove compressor. Drain
oil from compressor, and record amount of oil drained.
3) To install, reverse removal procedure. Using new
refrigerant oil, add to compressor the same amount of oil drained from
it. Evacuate and charge A/C system.
CONDENSER
NOTE: Before removing condenser, note location of radiator and
condenser air seals. If air seals are not installed properly,
A/C and engine cooling systems will not perform properly.
Removal
1) Disconnect negative battery cable. Discharge A/C system,
using approved refrigerant recovery/recycling equipment. Disconnect
A/C fittings at inlet and outlet of condenser. Plug or cover all
openings in A/C system.
2) On Dakota, remove bolts securing radiator and fan shroud
to inside of upper radiator crossmember. Remove top mounting bolts
securing condenser to upper crossmember. Tilt top of radiator and fan
shroud toward engine.
3) On Ram Pickup (gasoline engine), remove bolts securing
condenser upper mounting brackets to outside of upper radiator
crossmember. Tilt condenser away from engine compartment far enough to
grasp top of condenser with both hands. On Ram Pickup (diesel engine),\
remove bolts securing condenser to charge air cooler. On all models,
lift condenser assembly from vehicle.
Installation
To install, reverse removal procedure. Install new "O" rings
to fittings. Fill cooling system. Evacuate and charge A/C system.
EVAPORATOR CORE & HEATER CORE
Removal & Installation (Dakota & Durango - Front)
Remove instrument panel. See INSTRUMENT PANEL. Remove A/C-
heater assembly. See A/C-HEATER ASSEMBLY. With A/C-heater housing
removed, remove housing cover. Remove evaporator core or heater core