ect LEXUS SC300 1991 Service Repair Manual

TROUBLESHOOTING
You will find the cause of trouble more easily by properly using the table \
shown below. In this table, the num-
bers indicate the order priority of causes of trouble. Check each part in th\
e order shown. If necessary, re-
place the parts.
See pageB±4,21BE±26BE±4,20BE±91BE±90BE±92BE±91BE±93±
Trouble
Part Name
AM1 FuseIgnition SwitchWIPER FuseWiper SwitchWiper MotorWasher MotorWasher SwitchWasher Hose and NozzleWire Harness
Wipers and washers do not operate.*1132456
Wipers and washers do not operate.*221345
Wipers and washers do not operate.*31234
Wipers do not operate in LO, HI or MIST.123
Wipers do not operate in INT.123
Washer motor does not operate.213
Wipers do not operate when washer switch
is ON.12
Washer fluid does not spray.1
*1: Door Lock and Power Windows do not operate
*
2: Door Lock and Power Window are normal. Combination Meter and Turn Signal do not operate.
*
3: Combination Meter and Turn Signal are normal.
BE±94
±
BODY ELECTRICAL SYSTEM Wiper and Washer System
WhereEverybodyKnowsYourName

COMBINATION METER
±
BODY ELECTRICAL SYSTEM Combination MeterBE±95
WhereEverybodyKnowsYourName

DESCRIPTION
The combination meter has various meters and gauges which show the vehicle'\
s condition, warning lights which
monitor abnormalities in the vehicle and inform the driver, indicator lights which inform the driver of the condition
of each part of vehicle, and a function for illumination and brightness ad\
justment of meters and gauges.
The component parts of this system and their functions are described in \
the following table.
Parts NameFunction
SpeedometerThe speedometer needle moves in accordance with signals from the speed s\
ensor to
indicate the vehicle's speed.
TachometerThe tachometer needle moves in accordance with signals from the igniter \
to indicate the
engine's speed.
Water Temperatrue
GaugeThe water temperature gauge's needle moves in accordance with signals from the send-
er gauge and indicates the temperature of the engine coolant.
Fuel GaugeThe fuel gauge needle moves in accordance with signals from the sender g\
auge, indicat-
ing the amount of fuel remaining in the fuel tank.
OdometerThe odometer counts the total distance traveled by the vehicle in accord\
ance with pulse
signals from the speed sensor.
Twin Trip Switch
The twin trip meter counts the distance traveled by the vehicle in accor\
dance with pulse
signals from the speed sensor. It can be reset using a switch and can be used to switch
between trip meters A and B.
Circuit Plate
This plate contains the circuitry for each meter and gauge and for each \
warning light and
indicator light, as well as an internal engine oil level warning drive c\
ircuit, drive circuits for
the odometer and trip meter and brightness adjustment circuitry for each\
indicator.
Speed SensorMounted in the transmission, this sensor outputs pulse signals to the co\
mbination meter
in accordance with the speed of the output shaft.
Twin Trip SwitchOperation of this switch switches between the A and B trip meters and se\
nds reset sig-
nals to the combination meter.
Water
Temperature Sender
GaugeThis sender converts engine coolant temperatures to a resistance value i\
n signal form to
the combination meter.
Fuel Sender GaugeThis sender converts the level of fuel remaining in fuel tank to resista\
nce value and
sends the resistance value in signal form to combination meter.
Rheostat Light
Control VolumeIn order to adjust the degree of illumination of the combination meter, the resistance val-
ue of the built±in variable resistor is sent to the combination meter\
and rheostat light
control.
Fuel Level Warning
SwitchWhen the level of fuel remaining falls below a predetermined level, cont\
inuity is estab-
lished with this switch, which is built into the fuel sender gauge, caus\
ing a warning light
to light up.
Low Oil Pressure
Warning SwitchThis switch is mounted on the engine block. Continuity is established in\
this switch when
the oil pressure is low, causing a warning light to light up.
Integration Relay (Seat
Belt Warning Relay)
This relay receives current from fuse GAUGE and DOME and is connected to\
each
buckle switch, door courtesy switch, key unlock warning switch and warni\
ng light. As
part of the seat belt warning system, it sounds a chime and lights a war\
ning light when
seat belts are unfastened. As part of the key unlock warning system, it \
sounds a chime
when the set conditions are fulfilled.
Light Failure SensorThis sensor senses when a bulb in rear combination light is burnt out an\
d lights up a
warning light.
BE±96±
BODY ELECTRICAL SYSTEM Combination Meter
WhereEverybodyKnowsYourName

Parts NameFunction
Coolant Level
Warning SwitchThis switch is installed in the radiator reservoir tank. It lights up a \
warning light when the
coolant level becomes low.
Engine Oil Level
Warning SwitchThis switch is mounted in the engine oil pan. It lights a warning light \
when the engine oil
level is low.
Brake Fluid Level
Warning SwitchThis switch is mounted in the brake master cylinder reservoir tank. It l\
ights up a warning
light when the brake fluid level is low.
Parking Brake SwitchThis switch is on the parking brake lever bracket. Continuity in this sw\
itch is established
when the lever is released, causing a warning light to light up.
Door Courtesy SwitchContinuity is established in this switch when a door is opened, causing \
a warning light to
light up.
Warning LightsWhen an abnormality is detected in the vehicle, current is sent to these\
lights, or they are
grounded, causing them to light up.
Indicator LightsCurrent is sent to these lights, or they are grounded, causing them to l\
ight up and indicate
the vehicle's condition to the driver.
Window Washer Level
Warning SwitchThis switch is mounted in the window washer tank. It lights a warning li\
ght when the
window washer level becomes low.
±
BODY ELECTRICAL SYSTEM Cominbation MeterBE±97
WhereEverybodyKnowsYourName

Parts Location
BE±98±
BODY ELECTRICAL SYSTEM Combination Meter
WhereEverybodyKnowsYourName

Parts Location (Cont'd)
±
BODY ELECTRICAL SYSTEM Combination MeterBE±99
WhereEverybodyKnowsYourName

Wiring Diagram
BE±100±
BODY ELECTRICAL SYSTEM Combination Meter
WhereEverybodyKnowsYourName

Connector Diagrams
±
BODY ELECTRICAL SYSTEM Combination MeterBE±101
WhereEverybodyKnowsYourName

Water Temperature
Connector Diagrams (Cont'd)
BE±102±
BODY ELECTRICAL SYSTEM Combination Meter
WhereEverybodyKnowsYourName

Parts Inspection
(Combination Meter Assembly)
REMOVAL AND INSTALLATION OF
COMBINATION METER ASSEMBLY
1. REMOVE COMBINATION METER ASSEMBLY(a) Lower the steering wheel fully and set it in the far position.
(b) Turn the ignition switch to LOCK and disconnect battery terminals.
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and negative (±) terminal
cable is disconnected from the battery.
(c) Remove instrument cluster finish panel.
(d) Remove four screws and disconnect three connectors.
(e) Remove combination meter assembly.
2. INSTALL COMBINATION METER ASSEMBLY For installation, follow the removal procedure in reverse.
±
BODY ELECTRICAL SYSTEM Combination MeterBE±103
WhereEverybodyKnowsYourName