1995 TOYOTA SUPRA ignition

TROUBLESHOOTING
The table below will be useful for you in troubleshooting these electrical problems. The most likely causes
of the malfunction are shown in the order of their probability. Inspect each part in the order shown, and
replace the part when it is found to be faulty.
 Trouble Parts name (See page)
 
 
 
 
 
 
Wipers and washers do not operate.
 
 
 
 
 
 
1. ALT Fuse (BE±5)
2. AM1 Fuse (BE±5)
3. WIPER Fuse (BE±6)
4. Ignition Switch (BE±8)
5. Wiper and Washer Switch (BE±36)
6. Wire Harness
 
 

Front wiper does not operate.
 
 

1. Front Wiper and Washer Switch (BE±36)
2. Front Wiper Motor (BE±38)
3. Wire Harness
 
 
 Rear wiper does not operate.
 
 
 
1. Rear Wiper and Washer Switch (BE±37)
2. Rear Wiper Motor and Relay (BE±39)
3. Wire Harness
 
 
 Front washer does not operate.
 
 
 
1. Front Wiper and Washer Switch (BE±36)
2. Washer Motor (BE±39)
3. Wire Harness
 
 
 Rear washer does not operate.
 
 
 
1. Rear Wiper and Washer Switch (BE±37)
2. Washer Motor (BE±39)
3. Wire Harness
± BODY ELECTRICAL SYSTEMWIPER AND WASHER SYSTEMBE±35

WARNING LIGHTS
 Trouble Parts name (See page)
 
 
 
 
 
Warning lights do not light up
(Except Discharge and Door Open)
 
 
 
 
 
1. Bulb
2. IGN Fuse (BE±6)
3. Ignition Switch (BE±8)
4. Meter Circuit Plate (BE±44)
5. Wire Harness
6. Generator
 
 
 
 
 
 
Brake Warning Light does not light up
 
 
 
 
 
 
1. Bulb
2. Brake Fluid Level Warning Switch (BE±52)
3. Parking Brake Switch (BE±52)
4. Bulb Check Relay
5. Meter Circuit Plate (BE±44)
6. Wire Harness
 
 
 
 
 
Seat Belt Warning Light does not light up
 
 
 
 
 
1. Bulb
2. Seat Belt Buckle Switch (BE±56)
3. Integration Relay (BE±55)
4. Meter Circuit Plate (BE±44)
5. Wire Harness
 
 
 
 
Engine Oil Level Warning Light does not light up
 
 
 
 
1. Bulb
2. Engine Oil Level Switch (BE±51)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
Low Oil Pressure Warning Light does not light up
 
 
 
1. Bulb
2. Low Oil Pressure Warning Switch (BE±51)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
 
 
 
 
 
 
 
Door Open Warning Light does not light up
 
 
 
 
 
 
 
1. Bulb
2. DOME Fuse (BE±5)
3. Door Courtesy Switch (BE±54)
4. Luggage Room Light Switch (BE±28)
5. Integration Relay
6. Meter Circuit Plate (BE±44)
7. Wire Harness
 
 
 
 
Master Warning Light does not light up
 
 
 
 
1. Bulb
2. Telltale Light (BE±48)
3. Meter Circuit Plate (BE±44)
4. Wire Harness
BE±42± BODY ELECTRICAL SYSTEMCOMBINATION METER

OD TRIP METER INSPECTION
INSPECT OD/TRIP METER (in Telltale Light RH)
(a) Remove the telltale light with connector still connected.
(b) Check the continuity and voltage.
 
 Tester connection to
terminal number 
 Condition
 
 Specified condition
 
 7±Ground*1 
 Constant
 
 Continuity
 1±Ground*1 Ignition Switch ºONº position Battery positive voltage
 
 4±Ground*1 
 
Light Control Switch ºTAILº or ºHEADº
position 
 Battery positive voltage
 
 5±7*1 
 
Ignition Switch ON
Drive the vehicle slowly 
 0V e Battery positive voltage
 
 6±7*2 
 Ignition Switch ON
Drive the vehicle slowly 
 0V e more than 5V
 8±Ground*1 Constant Battery positive voltage 
 
 10±Ground*1
 
 
 
Ignition Switch ON, Light Control Switch
TAIL or HEAD, Turn the light control
Rheostat knob to clockwise
 
 
 6V " 0V
*1: If continuity or voltage are not as specified, check vehicle
side.
*
2: If voltage is not as specified, replace the telltale light.
FUEL GAUGE INSPECTION
1. INSPECT RECEIVER GAUGE OPERATION
(a) Disconnect the connector from the sender gauge assembly.
(b) Turn the ignition switch ON, check that the receiver gauge
needle indicates EMPTY.
(c) Connect terminals 2 and 3 on the wire harness side
connector through a 3.4 W test bulb.
(d) Turn the ignition switch ON, check that the bulb lights up and
receiver gauge needle moves toward the full side.
HINT: Because of the silicon oil in the gauge, it will take a
short time for the needle to stabilize.
If operation is not as specified, inspect the receiver gauge re-
sistance. BE±48
± BODY ELECTRICAL SYSTEMCOMBINATION METER

2. INSECT RECEIVER GAUGE RESISTANCE
Measure the resistance between terminals.
 Between terminals Resistance (
)
 A±B Approx. 269.7
 A±C Approx. 123.5
 B±C Approx. 146.2
If resistance value is not as specified, replace the fuel receiv-
er gauge.
3. INSPECT SENDER GAUGE RESISTANCE
Measure the resistance between terminals 2 and 3 for each
float position.
 
 Float position mm (in.)
 
 Resistance (
)
 F Approx. 33.8 (1.33) Approx. 4.0
 1/2 Approx. 44.8 (1.76) Approx. 55.0
 E Approx. 141.1 (5.55) Approx. 107.0
If resistance value is not as specified, replace the sender
gauge.
FUEL LEVEL WARNING INSPECTION
1. INSPECT WARNING LIGHT
(a) Disconnect the connector from the sender gauge.
(b) Connect terminals 1 and 3 on the wire harness side
connector.
(c) Turn the ignition switch ON, check that the warning light lights
up.
If the warning light does not light up, test the bulb or inspect
wire harness.
2. INSPECT SWITCH
(a) Apply battery positive voltage between terminals 1 and 3
through a 3.4 W test bulb, check that the bulb lights up.
HINT: It will take a short time for the bulb to light up.
(b) Submerge the switch in fuel, check that the bulb goes out.
If operation is not as specified, replace the sender gauge.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±49

ENGINE COOLANT TEMPERATURE
GAUGE INSPECTION
1. INSPECT RECEIVER GAUGE OPERATION
(a) Disconnect the connector from the sender gauge.
(b) Turn the ignition switch ON, check that the receiver gauge
needle indicates COOL.
(c) Ground terminal on the wire harness side connector through
a 3 W test bulb.
(d) Turn the ignition switch ON, check that the bulb lights up and
the receiver gauge needle moves toward the hot side.
If operation is as specified, replace the sender gauge.
Then recheck the system.
If operation is not as specified, measure the receiver gauge
resistance.
2. INSPECT RECEIVER GAUGE RESISTANCE
Measure the resistance between terminals.
HINT: Connect the test leads so that the current from the
ohmmeter can flow according to the chart order.
 Between terminals Resistance (
) 
A±B 
Approx. 229.7
 A±C Approx. 54.0
 B±C Approx. 175.7
If resistance value is not as specified, replace the engine
coolant temperature receiver gauge.
3. INSPECT SENDER GAUGE RESISTANCE
Measure the resistance between terminal and gauge body.
 Temperature °C (°F) Resistance (
)
 50 (122.0) 160 ~ 240
 120 (248.0) 17.1 ~ 21.2
If resistance value is not as specified, replace the engine
coolant temperature sender gauge. BE±50
± BODY ELECTRICAL SYSTEMCOMBINATION METER

LOW OIL PRESSURE WARNING
INSPECTION
1. INSPECT SWITCH
(a) Check that there is continuity between terminal and ground
with the engine stopped.
(b) Check that there is no continuity between terminal and
ground with the engine running.
HINT: Oil pressure should be over 29 kPa (0.3 kgf/ cm
2, 4.3
psi)
If operation is not as specified, replace the switch.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the warning switch and
ground terminal on the wire harness side connector.
(b) Turn the ignition switch ON, check that the warning light lights
up.
If the warning light does not light up, test the bulb or inspect
wire harness.
ENGINE OIL LEVEL WARNING
INSPECTION
1. INSPECT SWITCH
(a) Check that there is continuity between terminal with the
switch in each position.
(b) Heat the switch to above 60°C (140°F) in an oil bath.
(c) Check that there is continuity between terminals with the
switch ON (float up).
(d) Check that there is no continuity between terminals with the
switch OFF (float down).
If operation is not as specified, replace the switch.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the switch.
(b) Ground terminal 1 on the wire harness connector.
(c) Turn the ignition switch ON. Check that the warning light
lights up approximately 40 seconds later.
If the warning light does not light up, inspect bulb or wire har-
ness.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±51

LIGHT FAILURE SENSOR INSPECTION
1. INSPECT SENSOR CIRCUIT
Disconnect the connector from the sensor and inspect the
connector on the wire harness side, as shown.
 
 
 
Tester connection to
terminal number
 
 
 
Condition
 
 
 
Specified condition
 1±Ground Constant Continuity*
 2±Ground Constant Continuity*
 9±Ground Constant Continuity* 
 10±Ground
 
 Constant
 
 Continuity*
 11±Ground Constant Continuity
 12±Ground Constant Continuity*
 3±Ground Light control switch position OFF No Voltage 3±Ground Light control switch position TAIL or HEAD Battery positive voltage 
 4±Ground
 
 Ignition switch position LOCK or ACC
 
 No voltage
 4±Ground Ignition switch position ON Battery positive voltage
 7±Ground Stop light switch position OFF No voltage
 7±Ground Stop light switch position ON Battery positive voltage 
 8±Ground
 
 Engine condition Stop
 
 No voltage
 8±Ground Engine condition Running Battery positive voltage
*: There is resistance because this circuit is grounded
through the bulb.
If circuit is as specified, replace the sensor.
If the circuit is not as specified, inspect the circuits connected
to other parts.
2. INSPECT WARNING LIGHT
(a) Disconnect the connector from the light failure sensor and
ground terminal 4 on the wire harness side connector.
(b) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or inspect
wire harness.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±53

SEAT BELT WARNING INSPECTION
1. INSPECT INTEGRATION RELAY OPERATION
(a) Connect the positive (+) lead from the battery to terminals 1
and 7.
(b) Connect the positive (+) lead from the battery to terminal 9
through a 3.4W test bulb.
(c) Check that the test bulb lights up and buzzer sounds for 4±8
seconds when the negative (±) lead from the battery is
connected to terminal 10.
(d) Check that the buzzer sounding in (c) stops when the
negative (±) lead from the battery is connected to terminal 8.
If operation is not as specified, replace the integration relay.
2. INSPECT RELAY CIRCUIT
Remove the relay from the junction block No.1 and inspect
the connectors on the junction block side.
 
 Tester connection to
terminal number 
 Condition
 
 Specified condition
 4±Ground Driver's door open Continuity 
 4±Ground
 
 Driver's door close
 
 No continuity
 5±Ground Ignition key Set Continuity
 5±Ground Ignition key remove No continuity
 8±Ground Driver's seat belt fasten Continuity 
 8±Ground
 
 Driver's seat belt unfasten
 
 No continuity
 10±Ground Constant Continuity
 1±Ground Constant Battery positive voltage
 9±Ground Ignition switch position ON Battery positive voltage 
 9±Ground
 
 Ignition switch position LOCK or ACC
 
 No voltage
If circuit is not as specified, try replacing the relay with a new
one.
± BODY ELECTRICAL SYSTEMCOMBINATION METERBE±55