
AUDIO SYSTEM - Specifications 8-193
NOISE SOURCES
Source of Electrical System Noise
Ignition system
(1) Spark plug
(2) High tension cable
(3) Distributor Power generation system
(1) Ripple at contact between alternator
armature and carbon brush
(2) Spark from voltage regulator contact
!
Other electrical device
(1) Armature of wiper, blower and other
motors.
(2) Starter and switch when starting engine
(3) Spark from changeover switch
(4) Horn
(5) Contact of turn signal
(6) Loose contact of wiring harness
(7) Static electricity generated by tire or
generator drive-belt
(8) Voltage stability unit for instrument
Noise Sourse of Vehicle Equipment
Kind of noise
Whistling sound Equipment
Alternator Symptom of noise generation
Noise increases when accelerator pedal is
depressed and it subsides soon after engine
is stopped.
Scratching sound
Water temperature gauge unit Noise is produced while engine is running
and it persists for a while after engine
shutdown.
Fuel gauge unit Noise is produced at sudden acceleration,
driving on rough road or when ignition key is
placed to ON.
Jarring
Wish-wash,
wish-wash
Buzz, click Oil pressure switch
Flasher relay
Horn
Wiper motor
Washer motor Noise is produced with engine operation
and no noise is made when engine is idling.
Noise is produced with operation of turn
signal light
Noise is made when horn button is pressed
or released.
Whinning Noise is generated with the wiper speed.
Noise is made when washer is operated.
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AUTOMATIC FREE-WHEELING HUB INDICATOR SYSTEM - Generallnformation 8-211
3. Automatic free-wheeling hub in free condition
For the free condition, although there are (when the vehicle is traveling) output signals from the vehicle-
speed sensor, there are no signals from the pulse generator, with the result that the memory circuit is
erased (because reset signals are output from the lock-discrimination circuit), and so the indicaotr light
does not illuminate.
I
Lock Use-detection
-discrimination
Memory ipeed sensor Ignition switch
Automatic free-
detection circuit
circuit
circuit
Automatic free-wheeling
indicator control unit -
hub i
Sub fusible link
link
Pulse generator cross-sectional view PULSE GENERATOR
Coil hgnet
16W1547
rator
Front out-
put shaft
16W1546 The pulse generator is located at the rear part of the front
output shaft of the transfer, and is composed of the magnet,
the coil and the pole (iron core).
When a magnetic material (iron, nickel, etc.) is brought close
to and moved away from the pole (iron core), the magnetic flux
within the pole changes, thus generating AC voltage in the
coil.
Because the front output shaft does not rotate when the
automatic free-wheeling hub is in the free condition, there is
no generation of AC voltage in the pulse generator.
In the locked condition, however, the front output shaft and
the pulse rotor rotate, with the result that the magnetic flux
(within the p o e I (’ Iron core) of the pulse generator) changes in
accordance with the rotations of the pulse rotor, thereby
generating AC voltage in the coil.
This AC voltage is transmitted to the automatic free-wheeling
hub indicator control unit.
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8-212 AUTOMATIC FREE-WHEELING HUB lNCDlCATOR SYSTEM - $%%60n’~at’on’
Speedometer
I
iensor Vehicle-speed
sensor
16W1506
12R0058
Circuit Diagram
16W153
SPECIFICATIONS
GENERAL SPECIFICATIONS VEHICLE-SPEED SENSOR (REED-TYPE SWITCH)
The vehicle-speed sensor functions to substitute pulse signals
for the rotations (vehicle speed) of the transmission’s output
gear;/ t i is located within the speedometer.
Pulse signals are generated when the speedometer cable
rotates.
AUTbMATlC FREE-WHEELING HUB INDICATOR
CONTROL UNIT
The control unit is located at the upper part of the right cowl
side.
The control unit is composed of the pulse-detection circuit
(which receives the input signals from the pulse generator),
the vehicle-speed-detection circuit (which receives the input
signals from the vehicle-speed sensor), the lock-discrimination
circuit (which, based on both of these input signals, judges the
condition of the automatic free-wheeling hub ‘and then trans-
mits indicator output signals to the memory circuit), and the
memory circuit (which “memorizes” the indicator output
signals from the lock-discrimination circuti).
Items
Automatic free-wheeling hub indicator light
Pulse generator
Type
Vehicle-speed sensor
Type
Pulse generation
SERVICE SPECIFICATIONS
Specifications
W (SAE trade number) 1.4(74)
Magnet coil type
Reed switch type
4 pulses/ rotation
NOORG-
Items Specifications
Standard values
Pulse generator resistance
R 215-275
Vehicle-speed sensor output voltage V
When OFF 4 or more 1 STB Revision
When ON 0

24-20 AIR-CONDITION!NG-General Information
I
AIR-CONDITIONING SYSTEM COMPO
N24BBBB
Condenser MDuct, joint (Blower side)
oint (Heater unit
Condenser
2OWB31
Suction Pipe Receiver bracket side)
COMPRESSOR - The prime purpose of the compressor is to compress the low pressure refrigerant vapor
from the evaporator into a high pressure, high temperature vapor. The 6 cylinder 6P148 compressor is used.
MAGNETIC CLUTCH is mounted on the compressor providing a convenient way to drive and disengage
compressor in accordance to the cooling needs. CONDENSER is located in front of the radiator. Its function
is to cool the hot, high pressure refrigerant gas causing it to condense into high pressure liquid refrigerant.
RECEIVER DRIER is used to remove any traces of moisture from the refrigerant system. This component
incorporates the sight glass and fusible plug. SIGHT GLASS at the top of the receiver drier is provided as a
diagnostic tool to observe refrigerant flow and observe refrigerant level. THE FUSIBLE PLUG is located on
the receiver drier. Its function is to prevent damage to the air conditioning system in the event that
excessive pressure develops due to condenser air flow being restricted by, for example, leaves, newspaper,
an overcharge of refrigerant, or air in the system. LOW PRESSURE SWITCH prevents damage to the
compressor in case of system loss of refrigerant charge. EXPANSION VALVE - The expansion valve is used
for all applications. Its function is to meter refrigerant into the evaporator in accordance with cooling
requirements. EVAPORATOR COIL is located in the unit and its function is to cool and dehumidify the air
before it enters the vehicle. FREEZE UP CONTROL FIN THERMOSTAT SENSOR is installed at the heater
side of evaporator. The main function of a freeze control is to keep condensate water on the face of the
evaporator coil from freezing and restricting air flow. WATER TEMPERATURE SWITCH - When the
temperature of the radiator coolant became high, this switch functions to stop the compressor and prevent
engine overheating. SERVICE VALVE at the compressor and the discharge line. The valves are used to test
and service the refrigerant system. REFRIGERANT R-12 is used maximum amount 907 g (32 oz.) R-12.
COMPRESSOR OIL is used DENS0 oil 6 maximum amount 110 cc (3.7 U.S.fl.oz., 3.9 Imp.fl.oz.).
/ STB Revision

AIR-CONDITIONING -Specifications
SPECIFICATIONS
GENERAL SPECIFICATIONS
24-2 1
N24CA-
Items Specifications
Compressor
Model
6P148lnclined-plate type
No. of cylinders and displacement
6 cylinders 6,148 (208,216)
cc. (U.S.fl. oz., Imp.fl.02.)
Refrigeration unit lubricant
cc. (U.S.fl. oz., Imp.fl.oz.) DENS0 oil 6 110 (3.7,3.9)
Protective equipment
OFF: 1 .O (22) ON:4.5 (39)
Cycling clutch switch
“C(“F)
OFF:210 (30) ON:230 (33)
Low pressure switch
kPa (psi)
OFF: 113 (235) ON:106(222)
Water temperature switch
“C (“F)
Air temperature thermostat
Freezor prevention
“C (“F) OFF:3 (37.4) ON:5 (41)
Burn out temperature 106 (222)
Fusible plug “C (“F)
R-l 2 600-900 (1.3-2.0)
Refrigerant and quantity
g (Ibs.1
SERVICE SPECIFICATIONS N24CE-
Items Specifications
Standard value
Drive belt deflection mm (in.) 17.20 (.7-.8)
Pressure plate to rotor clearance mm (in.)
0.4-0.7 (.02-.03)
TORQUE SPECIFICATIONS N24CG Items Nm ftlbs.
Suction hose to cooling unit 30-35 22-25
Liquid pipe to cooling unit 12-15 9-l 1
Liquid pipe to receiver drier 12-15 9-l 1
Suction hose to suction hose 30-35 22-25
Liquid pipe to liquid pipe 12-15 9-l 1
Liquid pipe to condenser 20-25 15-18
Suction hose to compressor 30-35 22-25
Discharge hose to compressor 20-25 15-18
Discharge hose to liquid pipe 20-25 15-18
Compressor shaft nut 15-17 11-13
Through bolt 25-26 18-20
/ STB Revision I

AIR-CONDITIONING-Service Adjustment Procedures
SERVICE ADJUSTMENT PROCQDURES 24-29 N24FDAD
MANIFOLD GAUGE SET INSTALLATUON Discharge
W gauge
Suction
gauge
Suction
gauge
valve Manifold Gauge Valves should be closed
when connecting the manifold gauge set to the service port of the
compressor and the discharge hose. The suction gauge valve at the left is opened to provide a passage between
the suction gauge and the center manifold outlet. The discharge gauge valve at the right is opened to provide a
passage between the discharge pressure gauge and the center manifold outlet.
Detailed instructions for proper use of the gauge set manifold are contained in the text covering each test and
service operation employing these gauges.
Suction Gauge; the left side of the manifold set is calibrated to register 0 to-100 kPa (0 to 30 in. of vacuum) and
0 to 1000 kPa (0 to 150 psi). This gauge is connected to the suction port of the compressor.
Discharge Gauge; the right of the manifold set is calibrated to register 0 to 2100 kPa (0 to 300 psi). For all
tests this gauge is connected to the discharge port of the system.
Center Manifold Outlet provides the necessary connection for a long service hose used when discharging the
system, using a vacuum pump to “pull a vacuum” before charging the system, and for connecting the supply of
refrigerant when charging the system
glass -
2OW724 N24FEAE The receiver drier assembly consists of; Drier reservoir, Refriger-
ant level sight glass and Fusible plug.
To Test the Receiver Drier (1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the
received drier is restricted.
Replace the receiver drier.
SIGHT GLASS REFRlGERANT LEVEL TEST The sight glass is a refrigerant level indicator. To check the refrigerant level, clean the sight glass and start the
vehicle engine. Push the air conditioner button to operate the compressor, place the blower switch to high and
move the temperature lever to extreme left.
After operating for a few minutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged, the compressor discharge line is warm and the
compressor inlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged and there is no significant temperature difference
between compressor inlet and discharge lines; the system has lost some refrigerant.
(3) If the sight glass is clear and the magnetic clutch is disengaged; the clutch is faulty or, the system is out of
refrigerant. Perform low pressure switch test to determine condition. Check low pressure switch and clutch coil
for electrical continuity.
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24-28 AIR-CONDITIONING-Safety Precautions
SAFETY PRECAUTIONS N24PAAB
SAFETY PRECAUTIONS
I
The refrigerant used in all air-conditioning installations is R-12. It is transparent and colorless in both the liquid and
vapor state. Since it has a boiling point of -29.8T (-21.7”F). at atmospheric pressure, it will be a vapor at all normal
temperatures and pressures. The vapor is heavier than air, non- flammable, and nonexplosive. It is nonpoisonous
except when it is in direct contact with open flame. It is noncorrosive except when combined with water. The
following precautions must be observed when handling R-12.
Caution
Wear
safety goggles when servicing the refrigeration system.
R-12 evaporates so rapidly at normal atmospheric pressures and temperatures that it tends to freeze anything it
contacts. For this reason, extreme care must be taken to prevent any liquid refrigerant from contacting the skin and
especially the eyes.
Always wear safety goggles when servicing the refrigeration part of the air- conditioning system. Keep a bottle of
sterile mineral oil handy when working on the refrigeration system. Should any liquid refrigerant get into the eyes,
use a few drops of mineral oil to wash them out. RI12 is rapidly absorbed by the oil. Next, splash the eyes with
plenty of cold water. Call your doctor immediately even though irritation has ceased after treatment.
Caution
Do not heat R-12 above 52°C (125°F).
In most instances, moderate heat is required to bring the pressure of the refrigerant in its container above the
pressure of the system when charging or adding refrigerant. A bucket or large pan of hot water not over 52°C
(125°F) is all the heat required for this purpose. Do not heat the refrigerant container with a blow torch or any other
means that would raise temperature and pressure above this temperature. Do not weld or steam clean on or near
the system components or refrigerant lines.
Caution
Keep R-12 containers upright when charging the system.
When metering R-12 into the refrigeration system, keep the supply tank or cans in an upright position. If the
refrigerant container is on its side or upside down, liquid refrigerant will enter the system and damage the
compressor.
Caution
Always work in a well-ventilated room.
Good ventilation is vital in the working area. Always discharge the refrigerant into the service bay exhaust system
or outside the building. Large quantities of refrigerant vapor in a small, poorly ventilated room can displace the air
and cause suffocation.
Although R-12 vapor is normally nonpoisonous, contact with an open flame can cause the vapor to become very
poisonous. Do not discharge large quantities of refrigerant in an area having an open flame. A poisonous gas is
producted when using the flame-type leak detector. Avoid inhaling the fumes from the leak detector.
Caution
Do not allow liquid refrigerant to touch bright metal.
Refrigerant will tarnish bright metal and chrome surfaces, and in combination with moisture’can severely corrode
all metal surfaces.
/ STB Revision
-I

AIR-CONDITIONING-Service Adjustment Procedures
SERVICE ADJUSTMENT PROCQDURES 24-29 N24FDAD
MANIFOLD GAUGE SET INSTALLATUON Discharge
W gauge
Suction
gauge
Suction
gauge
valve Manifold Gauge Valves should be closed
when connecting the manifold gauge set to the service port of the
compressor and the discharge hose. The suction gauge valve at the left is opened to provide a passage between
the suction gauge and the center manifold outlet. The discharge gauge valve at the right is opened to provide a
passage between the discharge pressure gauge and the center manifold outlet.
Detailed instructions for proper use of the gauge set manifold are contained in the text covering each test and
service operation employing these gauges.
Suction Gauge; the left side of the manifold set is calibrated to register 0 to-100 kPa (0 to 30 in. of vacuum) and
0 to 1000 kPa (0 to 150 psi). This gauge is connected to the suction port of the compressor.
Discharge Gauge; the right of the manifold set is calibrated to register 0 to 2100 kPa (0 to 300 psi). For all
tests this gauge is connected to the discharge port of the system.
Center Manifold Outlet provides the necessary connection for a long service hose used when discharging the
system, using a vacuum pump to “pull a vacuum” before charging the system, and for connecting the supply of
refrigerant when charging the system
glass -
2OW724 N24FEAE The receiver drier assembly consists of; Drier reservoir, Refriger-
ant level sight glass and Fusible plug.
To Test the Receiver Drier (1) Operate the unit and check the piping temperature by
touching the receiver drier outlet and inlet.
(2) If there is a difference in the temperatures, the
received drier is restricted.
Replace the receiver drier.
SIGHT GLASS REFRlGERANT LEVEL TEST The sight glass is a refrigerant level indicator. To check the refrigerant level, clean the sight glass and start the
vehicle engine. Push the air conditioner button to operate the compressor, place the blower switch to high and
move the temperature lever to extreme left.
After operating for a few minutes in this manner, check the sight glass.
(1) If the sight glass is clear, the magnetic clutch is engaged, the compressor discharge line is warm and the
compressor inlet line is cool; the system has a full charge.
(2) If the sight glass is clear, the magnetic clutch is engaged and there is no significant temperature difference
between compressor inlet and discharge lines; the system has lost some refrigerant.
(3) If the sight glass is clear and the magnetic clutch is disengaged; the clutch is faulty or, the system is out of
refrigerant. Perform low pressure switch test to determine condition. Check low pressure switch and clutch coil
for electrical continuity.
1 STB Revision