1998 DODGE RAM 1500 fuse block

and coil are the only serviced parts on the compres-
sor.
A/C compressor clutch engagement is controlled by
several components: the A/C-heater control, A/C pres-
sure transducer, A/C compressor clutch relay, evapo-
rator temperature sensor and the powertrain control
module (PCM). The PCM may delay compressor
clutch engagement for up to thirty seconds (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). The battery must
be fully-charged before performing the following
tests. Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the A/C-heater controls in any A/C mode,
and the blower motor switch in the lowest speed
position, start the engine and run it at normal idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRB IIItscan tool and (Refer to
Appropriate Diagnostic Information) for testing of thecompressor clutch circuit and PCM control. The fol-
lowing components must be checked and repaired as
required before you can complete testing of the clutch
coil:
²Fuses in the junction block and the power distri-
bution center (PDC)
²A/C-heater control
²A/C compressor clutch relay
²A/C pressure transducer
²Evaporator temperature sensor
²Powertrain control module (PCM)
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is within
specifications with the electrical system voltage at
11.5 to 12.5 volts (Refer to 24 - HEATING & AIR
CONDITIONING - SPECIFICATIONS). This should
only be checked with the work area temperature at
21É C (70É F). If system voltage is more than 12.5
volts, add electrical loads by turning on electrical
accessories until the system voltage drops below 12.5
volts.
(a) If the clutch coil current reading is above
specifications, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
STANDARD PROCEDURE - A/C COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C-heater control to the
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
REMOVAL
The refrigerant system can remain fully-charged
during compressor clutch, rotor, or coil replacement.
The compressor clutch can be serviced in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the serpentine drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Disconnect the compressor clutch coil wire har-
ness connector.
(4) Remove the bolts that secure the compressor to
the mounting bracket.
(5) Remove the compressor from the mounting
bracket. Support the compressor in the engine com-
partment while servicing the clutch.
Fig. 1 Compressor Clutch - Typical
1 - CLUTCH PLATE
2 - SHAFT KEY (not used on KJ)
3 - ROTOR
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
24 - 10 CONTROLSDR
A/C COMPRESSOR CLUTCH/COIL (Continued)

(5) Install the HVAC housing (Refer to 24 - HEAT-
ING & AIR CONDITIONING/DISTRIBUTION/HVAC
HOUSING - INSTALLATION)
BLOWER MOTOR
DESCRIPTION
The blower motor and blower wheel are located in
the passenger side end of the HVAC housing, below
the glove box. The blower motor controls the velocity
of air flowing through the HVAC housing by spinning
a squirrel cage-type blower wheel within the housing
at the selected speed. The blower motor and wheel
can be removed from the housing inside the vehicle
without removing the instrument panel or HVAC
housing.
OPERATION
The blower motor will only operate with the igni-
tion switch in the On position and the A/C-heater
mode control switch in any position, except Off. The
blower motor receives a fused battery feed circuit
through a fuse in the Power Distribution Center
(PDC) whenever the ignition switch is in the On posi-
tion. Blower motor speed is controlled by regulating
the ground path through or around the blower motor
resistor block and through the A/C-heater blower
motor switch.
The blower motor and blower motor wheel are ser-
viced only as a unit and cannot be repaired and, if
faulty or damaged, must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
BLOWER MOTOR INOPERATIVE
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring, diagrams, proper wire and con-
nector repair procedures, further details on wire
harness routing and retention, as well as pin-out and
location views for the various wire harness connec-
tors, splices and grounds.
BLOWER MOTOR ELECTRICAL DIAGNOSIS
Refer to the Blower Motor Electrical Diagnosis
chart for basic checks of the blower motor circuit
(Fig. 3).
BLOWER MOTOR NOISE OR VIBRATION
Refer to the Blower Motor Noise/Vibration Diagno-
sis chart for basic checks of the blower motor when a
vibration or noise is present (Fig. 4).
24 - 28 DISTRIBUTIONDR
BLEND DOOR (Continued)

INTAKE AIR HEATER - OPERATION.......14-80
INTAKE AIR HEATER - REMOVAL........14-80
INTAKE AIR HEATER RELAY -
DESCRIPTION.......................14-82
INTAKE AIR HEATER RELAY -
INSTALLATION.......................14-82
INTAKE AIR HEATER RELAY -
OPERATION.........................14-82
INTAKE AIR HEATER RELAY - REMOVAL . . 14-82
INTAKE AIR TEMPERATURE SENSOR -
DESCRIPTION.......................14-30
INTAKE AIR TEMPERATURE SENSOR -
INSTALLATION.......................14-31
INTAKE AIR TEMPERATURE SENSOR -
OPERATION.........................14-30
INTAKE AIR TEMPERATURE SENSOR -
REMOVAL..........................14-30
INTAKE AIR TEMPERATURE SENSOR/
MAP SENSOR - DESCRIPTION..........14-82
INTAKE AIR TEMPERATURE SENSOR/
MAP SENSOR - INSTALLATION..........14-82
INTAKE AIR TEMPERATURE SENSOR/
MAP SENSOR - OPERATION............14-82
INTAKE AIR TEMPERATURE SENSOR/
MAP SENSOR - REMOVAL.............14-82
INTAKE MANIFOLD - CLEANING....9-160,9-226,
9-297
INTAKE MANIFOLD - DESCRIPTION . 9-159,9-225,
9-72
INTAKE MANIFOLD - INSPECTION . . 9-160,9-226,
9-297
INTAKE MANIFOLD - INSTALLATION.....9-160,
9-226,9-298,9-73
INTAKE MANIFOLD - REMOVAL....9-159,9-226,
9-297,9-73
INTAKE MANIFOLD LEAKAGE -
DIAGNOSIS AND TESTING........9-159,9-225
INTAKE MANIFOLD LEAKS - DIAGNOSIS
AND TESTING........................9-72
INTAKE SYSTEM - INSTALLATION, AIR....9-199
INTAKE SYSTEM - REMOVAL, AIR.......9-199
INTAKE/EXHAUST VALVES & SEATS -
DESCRIPTION..............9-123,9-256,9-28
INTAKE/EXHAUST VALVES & SEATS -
INSTALLATION...................9-124,9-30
INTAKE/EXHAUST VALVES & SEATS -
REMOVAL......................9-124,9-29
INTEGRATED POWER MODULE -
DESCRIPTION.....................8W-97-3
INTEGRATED POWER MODULE -
INSTALLATION....................8W-97-4
INTEGRATED POWER MODULE -
OPERATION.......................8W-97-3
INTEGRATED POWER MODULE -
REMOVAL........................8W-97-3
INTERIOR - CAUTION.................23-62
INTERLOCK - ADJUSTMENTS, BRAKE
TRANSMISSION SHIFT.........21-196,21-365
INTERLOCK - DIAGNOSIS AND TESTING,
BRAKE TRANSMISSION SHIFT . . . 21-196,21-364
INTERLOCK SYSTEM - DESCRIPTION,
BRAKE TRANSMISSION SHIFT . . . 21-196,21-364
INTERLOCK SYSTEM - OPERATION,
BRAKE TRANSMISSION SHIFT . . . 21-196,21-364
INTERNATIONAL SYMBOLS -
DESCRIPTION......................Intro.-5
INVERTED FLARING - STANDARD
PROCEDURE, DOUBLE.................5-10
IOD FUSE - DESCRIPTION...........8W-97-6
IOD FUSE - INSTALLATION...........8W-97-7
IOD FUSE - OPERATION.............8W-97-6
IOD FUSE - REMOVAL..............8W-97-7
ISO FLARING - STANDARD PROCEDURE
. . . 5-11
ISOLATORS - INSTALLATION, BODY
......23-37
ISOLATORS - REMOVAL, BODY
.........23-36
JOINT - DIAGNOSIS AND TESTING,
LOWER BALL
....................2-19,2-34
JOINT - DIAGNOSIS AND TESTING,
UPPER BALL
.....................2-27,2-36
JOINT - INSTALLATION, LOWER BALL
. 2-20,2-35
JOINT - INSTALLATION, UPPER BALL
.....2-36
JOINT - REMOVAL, LOWER BALL
.....2-19,2-35
JOINT - REMOVAL, UPPER BALL
.........2-36
JOINT-INNER - INSTALLATION, CV
........3-25
JOINT-INNER - REMOVAL, CV
............3-25
JOINT-OUTER - INSTALLATION, CV
........3-23
JOINT-OUTER - REMOVAL, CV
...........3-22JOINTS - ASSEMBLY, DOUBLE CARDAN
UNIVERSAL..........................3-17
JOINTS - DISASSEMBLY, DOUBLE
CARDAN UNIVERSAL..................3-16
JOUNCE BUMPER - INSTALLATION.......2-43
JOUNCE BUMPER - REMOVAL...........2-43
JOURNAL CLEARANCE - STANDARD
PROCEDURE, CONNECTING ROD
BEARING AND CRANKSHAFT...........9-272
JUMP STARTING - STANDARD
PROCEDURE.........................0-19
JUNCTION BLOCK - INSTALLATION,
BRAKE..............................5-24
JUNCTION BLOCK - REMOVAL, BRAKE....5-24
KEY CYLINDER - INSTALLATION.........19-12
KEY CYLINDER - REMOVAL............19-12
KEY IMMOBILIZER MODULE -
DESCRIPTION, SENTRY................8E-13
KEY IMMOBILIZER MODULE -
INSTALLATION, SENTRY...............8E-15
KEY IMMOBILIZER MODULE -
OPERATION, SENTRY.................8E-13
KEY IMMOBILIZER MODULE - REMOVAL,
SENTRY............................8E-15
KEY IMMOBILIZER MODULE (SKIM) -
DESCRIPTION, SENTRY................8Q-1
KEY IMMOBILIZER MODULE (SKIM) -
OPERATION, SENTRY..................8Q-2
KEY IMMOBILIZER SYSTEM INDICATOR
LAMP - DESCRIPTION, SENTRY..........8Q-5
KEY IMMOBILIZER SYSTEM INDICATOR
LAMP - OPERATION, SENTRY...........8Q-5
KEY IMMOBILIZER SYSTEM
INITIALIZATION, STANDARD
PROCEDURE - SENTRY................8Q-3
KEY IMMOBILIZER SYSTEM (SKIS) -
DESCRIPTION, SENTRY................8Q-1
KEY IMMOBILIZER SYSTEM (SKIS) -
OPERATION, SENTRY..................8Q-2
KEY IMMOBILIZER SYSTEM
TRANSPONDER PROGRAMMING,
STANDARD PROCEDURE - SENTRY.......8Q-4
KEY LOCK CYLINDER - DIAGNOSIS AND
TESTING, IGNITION SWITCH............19-11
KEY-IN IGNITION SWITCH -
DESCRIPTION.......................19-11
KEYLESS ENTRY MODULE -
DESCRIPTION, REMOTE................8N-7
KEYLESS ENTRY MODULE - DIAGNOSIS
AND TESTING, REMOTE................8N-7
KEYLESS ENTRY MODULE -
INSTALLATION, REMOTE...............8N-8
KEYLESS ENTRY MODULE - OPERATION,
REMOTE............................8N-7
KEYLESS ENTRY MODULE - REMOVAL,
REMOTE............................8N-7
KEYLESS ENTRY TRANSMITTER -
DIAGNOSIS AND TESTING, REMOTE......8N-8
KEYLESS ENTRY TRANSMITTER -
SPECIFICATIONS, REMOTE..............8N-9
KNOB RELEASE - INSTALLATION, TILT
LEVER.............................19-16
KNOB RELEASE - REMOVAL, TILT LEVER . . 19-16
KNOCK SENSOR - DESCRIPTION.........8I-14
KNOCK SENSOR - INSTALLATION........8I-15
KNOCK SENSOR - OPERATION..........8I-14
KNOCK SENSOR - REMOVAL............8I-15
KNUCKLE - DESCRIPTION...............2-18
KNUCKLE - INSTALLATION..........2-19,2-37
KNUCKLE - OPERATION................2-18
KNUCKLE - REMOVAL..............2-18,2-37
LABEL - DESCRIPTION, VEHICLE
CERTIFICATION....................Intro.-11
LAMP - DESCRIPTION, DOME...........8L-26
LAMP - DESCRIPTION, READING........8L-28
LAMP - DESCRIPTION, SENTRY KEY
IMMOBILIZER SYSTEM INDICATOR.......8Q-5
LAMP - INSTALLATION, CAB CLEARANCE . 8L-12
LAMP - INSTALLATION, CENTER HIGH
MOUNTED STOP.....................8L-11
LAMP - INSTALLATION, DOME..........8L-26
LAMP - INSTALLATION, FENDER
MARKER
...........................8L-18
LAMP - INSTALLATION, FOG
............8L-12
LAMP - INSTALLATION, LICENSE PLATE
. . 8L-17
LAMP - INSTALLATION, PARK/TURN
SIGNAL
............................8L-21
LAMP - INSTALLATION, READING
........8L-29LAMP - INSTALLATION, TAILGATE
MARKER...........................8L-18
LAMP - INSTALLATION, UNDERHOOD....8L-25
LAMP - OPERATION, DOME............8L-26
LAMP - OPERATION, READING..........8L-28
LAMP - OPERATION, SENTRY KEY
IMMOBILIZER SYSTEM INDICATOR.......8Q-5
LAMP - REMOVAL, CAB CLEARANCE.....8L-11
LAMP - REMOVAL, CENTER HIGH
MOUNTED STOP.....................8L-11
LAMP - REMOVAL, DOME..............8L-26
LAMP - REMOVAL, FENDER MARKER....8L-17
LAMP - REMOVAL, FOG...............8L-12
LAMP - REMOVAL, LICENSE PLATE......8L-17
LAMP - REMOVAL, PARK/TURN SIGNAL . . 8L-21
LAMP - REMOVAL, READING...........8L-28
LAMP - REMOVAL, TAILGATE MARKER . . . 8L-18
LAMP - REMOVAL, UNDERHOOD........8L-25
LAMP INDICATOR - DESCRIPTION,
CARGO.............................8J-20
LAMP INDICATOR - OPERATION, CARGO . . 8J-20
LAMP (MIL) - DESCRIPTION,
MALFUNCTION INDICATOR.............8J-31
LAMP (MIL) - OPERATION,
MALFUNCTION INDICATOR.............8J-31
LAMP OUT INDICATOR - DESCRIPTION . . . 8J-29
LAMP OUT INDICATOR - OPERATION.....8J-29
LAMP RELAY - DESCRIPTION, FOG......8L-12
LAMP RELAY - DESCRIPTION, PARK.....8L-20
LAMP RELAY - DIAGNOSIS AND
TESTING, PARK......................8L-20
LAMP RELAY - INSTALLATION, FOG......8L-13
LAMP RELAY - INSTALLATION, PARK.....8L-21
LAMP RELAY - OPERATION, FOG........8L-13
LAMP RELAY - OPERATION, PARK.......8L-20
LAMP RELAY - REMOVAL, FOG.........8L-13
LAMP RELAY - REMOVAL, PARK........8L-21
LAMP REPLACEMENT - STANDARD
PROCEDURE, MODULE................8M-3
LAMP REPLACEMENT - STANDARD
PROCEDURE, READING/COURTESY.......8M-3
LAMP SWITCH - DESCRIPTION, BACKUP . . . 8L-8
LAMP SWITCH - DESCRIPTION, BRAKE....8L-9
LAMP SWITCH - DIAGNOSIS AND
TESTING, BACKUP.....................8L-8
LAMP SWITCH - DIAGNOSIS AND
TESTING, BRAKE.....................8L-10
LAMP SWITCH - INSTALLATION, BRAKE . . 8L-11
LAMP SWITCH - OPERATION, BACKUP....8L-8
LAMP SWITCH - OPERATION, BRAKE......8L-9
LAMP SWITCH - REMOVAL, BRAKE......8L-10
LAMP UNIT - INSTALLATION, CENTER
HIGH MOUNTED STOP................8L-11
LAMP UNIT - INSTALLATION, LICENSE
PLATE .............................8L-17
LAMP UNIT - INSTALLATION,
UNDERHOOD........................8L-25
LAMP UNIT - REMOVAL, CENTER HIGH
MOUNTED STOP.....................8L-11
LAMP UNIT - REMOVAL, LICENSE PLATE . . 8L-17
LAMP UNIT - REMOVAL, UNDERHOOD . . . 8L-25
LAMPS, SPECIFICATIONS - EXTERIOR.....8L-7
LAMPS/LIGHTING - EXTERIOR -
DESCRIPTION........................8L-2
LAMPS/LIGHTING - EXTERIOR -
DIAGNOSIS AND TESTING..............8L-3
LAMPS/LIGHTING - EXTERIOR -
OPERATION..........................8L-2
LAMP/SWITCH - INSTALLATION, GLOVE
BOX ...............................8L-28
LAMP/SWITCH - REMOVAL, GLOVE BOX . . 8L-27
LASH ADJUSTER - DIAGNOSIS AND
TESTING, HYDRAULIC.............9-125,9-32
LASH ADJUSTMENT AND VERIFICATION
- STANDARD PROCEDURE, VALVE.......9-259
LATCH - INSTALLATION.....23-16,23-23,23-32,
23-47
LATCH - INSTALLATION, GLOVE BOX.....23-52
LATCH - INSTALLATION, UNDER SEAT
STORAGE BIN.......................23-80
LATCH - REMOVAL
....23-16,23-23,23-32,23-47
LATCH - REMOVAL, GLOVE BOX
.........23-52
LATCH - REMOVAL, UNDER SEAT
STORAGE BIN
.......................23-80
LATCH RELEASE CABLE/HANDLE
ASSEMBLY - INSTALLATION
............23-47
LATCH RELEASE CABLE/HANDLE
ASSEMBLY - REMOVAL
................23-47
18 INDEXDR
Description Group-Page Description Group-Page Description Group-Page