Ground DODGE RAM 1999 Service Repair Manual

"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

“O” ABBREVIATION TABLE (con’t) ABBREVIATION DEFINITION OHC Overhead Camshaft ORG Orange OSC Output State Check Opt. Option or Optional oz. Ounce ozs. Ounces

"P" ABBREVIATION TABLE

"P" ABBREVIATION TABLE
ABBREVIATION DEFINITION P Park P/C Printed Circuit P/N Park/Neutral P/S Power Steering PAV Pulse Air Valve PC-SOL Purge Control Solenoid PCM Powertrain Control module PCS Purge Control Solenoid PCSDM Passenger Compartment Sensor/Diagnostic Module PCV Positive Crankcase Ventilation PFE Pressure Feedback EGR sensor or circuit PFI Port Fuel Injection (see MA SEFI) PGM-CARB Programmed Carburetor PGM-FI Programmed Fuel Injection PIP Profile Ignition Pickup PNK Pink PPL Purple PRNDL Park Reverse Neutral Drive Low PROM Programmable Read-Only Memory psi Pounds Per Square Inch PSPS Power Steering Pressure Switch PTC Positive Temperature Coefficient PTO Power Take-Off PWR GND Power Ground circuit Pkg. Package Press. Pressure Prog. Programmed or Programmable Pts. Pints Pwr. Power

"Q" ABBREVIATION TABLE
"Q" ABBREVIATION TABLE
ABBREVIATION DEFINITION Qts.
Quarts

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.

OPERATION
CONTROL PANEL
Blower Motor Switch
Fan speed is controlled with a rotary switch. On front A/C-
heater systems, there are 4 different fan speed settings. Low, medium-
low, medium-high, and high. On rear A/C-heater systems, there are 3
different fan speed settings. Low, medium, and high.
Mode Control Knob
Mode rotary switch is used to change direction of air flow.
There are 7 different modes of operation: recirculation, panel with
A/C, floor/panel, panel without A/C (vent), floor, floor/defrost, and
defrost.
Temperature Control Knob
Temperature rotary switch controls temperature blend/air door
position by a cable on Dakota and Durango, and by vacuum actuator for
Ram Pickup. When cold temperature is selected, no air flows across
heater core. When hot temperature is selected, all air flows through
heater core. Temperature may vary by any setting between cold and hot.
CLUTCH CYCLING PRESSURE SWITCH
Dakota & Ram Pickup
Clutch cycling low pressure switch is mounted on a Schrader-
type valve fitting that is part of the accumulator. It is connected in
series with the high pressure cut-off switch and control panel,
between ground and PCM. Switch contacts open and close due to changes
in A/C system pressure. Opening and closing of switches will cause PCM
to turn compressor clutch on and off, regulating system pressure which
controls temperature of evaporator.
Clutch cycling low pressure switch contacts are normally open
when suction (low side) pressure drops below 25 psi (1.8 kg/cm
) on
Ram Pickup; 20.5 psi (1.4 kg/cm) on Dakota. Extreme cold weather will
also open contacts. When contacts are open, PCM will de-energize
compressor clutch relay, disengaging compressor clutch.
Clutch cycling pressure switch contacts will close when
suction (low side) pressure rises above 43 psi (3.0 kg/cm
) on Ram
Pickup or 36 psi (2.5 kg/cm) on Dakota. When contacts are closed, PCM
will energize compressor clutch relay, engaging compressor clutch.
ELECTRONIC CYCLING CLUTCH SWITCH
Durango
The electronic cycling clutch switch is mounted to Thermal
Expansion Valve (TXV), also referred to as an "H" valve, in engine
compartment. It provides evaporator temperature to the PCM. Using this
information, the PCM will cycle the compressor clutch to prevent
evaporator icing. The switch is used for the front evaporator only.
Electronic cycling clutch switch is connected in series with
mode control switch, high pressure cut-out switch, low pressure cut-
out switch, and PCM. The electronic cycling clutch switch opens when
refrigerant temperature is below about 37
F (2.8C) and will close
when refrigerant temperature is about 40F (4.4C).
FIXED ORIFICE TUBE
Dakota & Ram Pickup
The fixed orifice tube is located in outlet line of the
condenser. The orifice tube inlet and outlet ends have a screen to

filter the refrigerant. The orifice tube is used to meter the flow of
liquid refrigerant into the evaporator core.
HIGH PRESSURE CUT-OUT SWITCH
High pressure cut-out switch is located on compressor
discharge line, near compressor. On Dakota and Ram Pickup, it is
connected in series with the clutch cycling pressure switch and
control panel, between ground and PCM.
On Durango, it is connected in series with the electronic
cycling clutch switch, low pressure cut-out switch and control panel,
between ground and PCM. PCM controls compressor clutch operation.
On all models, when discharge pressure reaches 450-490 psi
(31.6-34.5 kg/cm
), high pressure cut-out switch interrupts A/C
request signal to PCM. PCM de-energizes compressor clutch relay,
disengaging compressor clutch. When discharge pressure drops to 270-
330 psi (23.2-19 kg/cm
) switch will close, thus restoring A/C request
signal to PCM.
HIGH PRESSURE RELIEF VALVE
High pressure relief valve is located on compressor manifold.
Valve vents system pressure if pressure is greater than 500-600 psi
(35.1-42.2 kg/cm
). Valve will reset when pressure decreases to 400
psi (28.1 kg/cm).
LOW PRESSURE CUT-OUT SWITCH OPERATION
Durango
Low pressure cut-out switch is located on suction line near
firewall. It is connected in series with the electronic cycling clutch
switch, high pressure cut-out switch and control panel, between ground
and PCM. PCM controls compressor clutch operation.
When discharge pressure reaches 10 psi (.7 kg/cm
), switch
interrupts A/C request signal to PCM. PCM de-energizes compressor
clutch relay, disengaging compressor clutch. When discharge pressure
increases to 13-27 psi (.9-1.9 kg/cm
), switch will close thus
restoring A/C request signal to PCM.
ADJUSTMENTS
TEMPERATURE CONTROL CABLE ADJUSTMENT
Dakota & Durango
1) Ensure temperature control cable housing and core are
connected at both A/C-heater control panel and A/C-heater assembly.
Ensure A/C-heater control panel is installed.
2) Rotate temperature control knob so that knob pointer is at
12 o'clock position. Pull temperature control knob straight out from
A/C-heater control panel until perimeter of knob (not knob pointer)
protrudes about .25" (6 mm) from face of A/C-heater control panel.
3) Rotate temperature control knob clockwise so that knob
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 A/C-heater control panel until perimeter of knob (not

A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS (RAM PICKUP)








\









\









\









\









\









\









\







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)









\









\









\









\









\









\









\







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

control panel and blower motor.
Fig. 3: Identifying Blower Motor Switch Connector Terminals (Typical)\
Courtesy of Chrysler Corp.
Rear (Durango)
1) Disconnect negative battery cable. Remove rear blower
motor switch located in headliner. See BLOWER MOTOR SWITCH (REAR)
under REMOVAL & INSTALLATION. Disconnect rear blower motor switch
connector. Using an ohmmeter, check continuity between rear blower
motor switch connector Black wire and ground. If continuity exists, go
to next step. If continuity does not exist, repair open in Black wire
between rear blower motor switch connector and ground connector
located at left rear of vehicle body.
2) Place blower motor switch knob to any position except OFF.
Using an ohmmeter, check for continuity between rear blower motor
switch connector Black wire and Black/Light Blue wire, and
Black/Orange wire and Dark Green wire while rotating blower motor
switch.
3) If continuity does not exist at any terminal, replace
faulty blower motor switch. If continuity exists as specified, check
for open in circuits between blower motor switch and blower motor
resistor. Also check for an open in circuit between blower motor
switch connector and blower motor relay.
CLUTCH CYCLING PRESSURE SWITCH
Dakota & Ram Pickup
1) Locate clutch cycling pressure switch on side or top of
A/C accumulator. Ensure clutch cycling pressure switch is properly
installed on A/C accumulator fitting. Ensure system pressure is
correct. See A/C SYSTEM PERFORMANCE test.
2) Start and run engine with A/C on. If clutch cycles, turn
engine off and disconnect negative battery cable. Disconnect clutch
cycling pressure switch connector. Place a jumper wire across
terminals of clutch cycling pressure switch harness connector. Connect
negative battery cable. Connect manifold gauge set. Set A/C-heater

6) Remove glove box. Reach through glove box opening and
disconnect antenna coaxial cable connector. Disconnect blower motor
connector located above glove box opening, near support brace for A/C-
heater housing. Disconnect radio ground strap. Loosen instrument panel
roll down bracket bolts about 2 turns, located at lower corners on
both sides of instrument panel. Remove 5 screws across top of dash
panel at base of windshield, removing center screw last.
7) Roll down instrument panel and install a temporary support
hook that is about 18" (457 mm) in length. Install hook from center
hole in instrument panel to center hole of dash panel. Pull lower
instrument panel outward until both roll down bracket bolts are in
slotted roll down position. Instrument panel should now be supported
and away from firewall.
8) Disconnect 2 door harness connectors, located on a bracket
near right end of instrument panel. Disconnect blower motor resistor.
Disconnect temperature control cable from A/C-heater housing and
remove from housing. See Fig. 5. Disconnect demister duct flexible
hose from A/C-heater housing.
9) Ensure instrument panel is free and clear for removal.
With the aid of an assistant, remove temporary support hook. Lift
instrument panel off of roll down bracket bolts and remove from
vehicle.
10) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.
Removal & Installation (Ram Pickup)
1) Disable air bag system. See AIR BAG SYSTEM SAFETY article.
Disconnect negative battery cable. Drain cooling system. Remove left
and right kick panel trim. Remove 5 screws and knee bolster/steering
column cover. Remove hood release and parking brake release handle
screws from lower instrument panel support. Remove 6 screws and
instrument panel support. Disconnect air bag connector at lower left
corner of instrument panel.
2) Pull PRNDL cable and twist to remove from position arm.
Push tab on bottom of cable retainer upward, then squeeze sides to
remove retainer from column. Remove tilt lever (tilt column only).
Remove both upper and lower shrouds from column. Remove lower fixed
column shroud. Loosen multifunction switch connector screw. Screw will
remain in connector.
3) Remove remaining steering column electrical connectors.
Remove air bag wiring harness from steering column wiring trough.
Remove wiring trough from steering column. Remove 3 toe plate nuts and
washers.
4) Remove 2 nuts and washers attaching steering column
bracket to instrument panel steering column support bracket. Allow
column to lower and rest on seat. Remove 2 screws from bottom of Air
Bag Control Module (ACM) cover. Remove 4 screws holding ACM to
transmission tunnel.
5) Disconnect wiring at ACM. Disconnect instrument panel left
side wiring connectors. Remove screw holding brake release to bottom
of instrument panel. Disconnect instrument panel right side wiring
connectors, which includes 2 connectors attached to A/C-heater
assembly housing, courtesy light connector, antenna cable and 2 body
connectors. Disconnect vacuum harness from A/C-heater system.
6) Remove 5 screws holding instrument panel to dash. Loosen
lower instrument panel pivot bolts. Roll instrument panel downward.
Remove instrument panel from vehicle.
7) To install, reverse removal procedure. Ensure all wiring
and hoses are clear and not pinched. Tighten bolts and nuts to
specification. See TORQUE SPECIFICATIONS . Enable air bag system. See
AIR BAG SYSTEM SAFETY article.

HIGH
Some possible causes of low side system pressure being high-
to-normal and high side system pressure being too high include:
* Condenser air flow restricted.
* Inoperative cooling fan.
* Faulty expansion valve.
* Refrigerant system overcharged.
* Air in refrigerant system.
* Engine overheating.
LOW SIDE PRESSURE IS HIGH & HIGH SIDE PRESSURE IS LOW
Some possible causes of low side system pressure being too
high and high side system pressure being too low include:
* Compressor belt is slipping.
* Fixed orifice tube not installed.
* Faulty compressor.
LOW SIDE PRESSURE IS LOW & HIGH SIDE PRESSURE IS HIGH
Some possible causes of low side system pressure being too
low and high side system pressure being too high include:
* Restricted refrigerant flow through refrigerant lines.
* Restricted refrigerant flow through expansion valve.
* Restricted refrigerant flow through fixed orifice tube.
* Restricted refrigerant flow through receiver-drier.
* Restricted refrigerant flow through condenser.
BLOWER MOTOR DIAGNOSIS
BLOWER MOTOR INOPERATIVE
Some possible causes of an inoperative blower motor include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor ground circuit wire harness or
connector.
* Faulty blower motor resistor.
* Faulty blower motor relay.
* Faulty blower motor switch.
* Faulty A/C-heater mode control switch.
* Faulty blower motor.
BLOWER NOT OPERATING IN ALL SPEEDS
Possible causes of the blower not operating in all speeds
include:
* Faulty fuse.
* Faulty blower motor feed circuit wire harness or
connectors.
* Faulty blower motor relay.
* Faulty blower motor resistor.
* Faulty blower motor switch.