1997 TOYOTA SUPRA relay

3
HOW TO USE THIS MANUAL B
This manual provides information on the electrical circuits installed on vehicles
by dividing them into a circuit for each system.
The actual wiring of each system circuit is shown from the point where the power
source is received from the battery as far as each ground point. (All circuit
diagrams are shown with the switches in the OFF position.)
When troubleshooting any problem, first understand the operation of the circuit
where the problem was detected (see System Circuit section), the power source
supplying power to that circuit (see Power Source section), and the ground
points (see Ground Points section). See the System Outline to understand the
circuit operation.
When the circuit operation is understood, begin troubleshooting of the problem
circuit to isolate the cause. Use Relay Location and Electrical Wiring Routing
sections to find each part, junction block and wiring harness connectors, wiring
harness and wiring harness connectors, splice points, and ground points of each
system circuit. Internal wiring for each junction block is also provided for better
understanding of connection within a junction block.
Wiring related to each system is indicated in each system circuit by arrows
(from
,to ). When overall connections are required, see the Overall Electrical
Wiring Diagram at the end of this manual.

5
B
I :Junction Block (The number in the circle is the
J/B No. and the connector code is shown beside
it). Junction Blocks are shaded to clearly
separate them from other parts .
A :System Title
B :Indicates a Relay Block. No shading is used and only the
Relay Block No. is shown to distinguish it from the J/B.
Example: 1 Indicates Relay Block No. 1.
C :Indicates the connector to be connected to a
part (the numeral indicates the pin No.)
Explanation of pin use.J :Indicates the wiring color.
Wire colors are indicated by an alphabetical code.
B = Black
BR = Brown
G = Green
GR = GrayL = Black
LG = Light Green
O = Orange
P = PinkR = Red
V = Violet
W = White
Y = Yellow
The first letter indicates the basic wire color and the second
letter indicates the color of the stripe.
D :Connector Color Connectors not indicated are milky
white in color:
E :( ) is used to indicate different wiring and connector, etc.
when the vehicle model, engine type, or specification is
different.
F :Indicates related system.
G :Indicates the wiring harness and wiring harness
connector. The wiring harness with male terminal is
shown with arrows ( ).
Example: L - Y
K :Indicates a wiring Splice Point (Codes are Eº for
the Engine Room, Iº for the Instrument Panel,
and Bº for the Body).
Example:
The Location of Splice Point I 5 is indicated by the shaded
section.
L :Page No.
M :Indicates a shielded cable.
Example:N :Indicates a ground point.
The first letter of the code for each ground point(s) indicates
the component's location, e.g. Eº for the Engine
Compartment, Iº for the Instrument Panel and Surrounding
area, and Bº for the Body and Surrounding area.
The first letter of the code for each wiring harness and wiring
harness connector(s) indicates thecomponent's location, e.g,
Eº for the Engine Compartment, Iº for the Instrument Panel
and Surrounding area, and Bº for the Body and Surrounding
area.
When more than one code has the first and second letters in
common, followed by numbers (e.g, IH1, IH2), this indicates
the same type of wiring harness and wiring harness connector.
P :When 2 parts both use one connector in common, the parts
connector name used in the wire routing section is shown in
square brackets [ ]. O :Indicates the pin number of the connector.
The numbering system is different for female and male
connectors.
H :Represents a part (all parts are shown in sky
blue). The code is the same as the code used in
parts position.
3B indicates
that it is inside
Junction Block
No. 3. v
v The pins shown are only for the highest grade, or only
include those in the specification.
lower rightlower left
(blue) (yellow)

6
B HOW TO USE THIS MANUAL
WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS TO TERMINAL 3 OF THE POWER WINDOW MASTER SW, TERMINAL 2 OF THE POWER WINDOW CONTROL
RELAY AND TERMINAL 8 OF THE POWER WINDOW SW THROUGH THE DOOR FUSE.
1. DRIVER'S WINDOW MANUAL UPº OPERATION BY MASTER SW
HOLDING MANUAL SW (DRIVER'S) ON UPº POSITION LOCATED IN POWER WINDOW MASTER SW, THE CURRENT FLOWS TO TERMINAL 5 OF THE POWER WINDOW CON-
TROL RELAY THROUGH TERMINAL 3 OF THE MASTER SW TERMINAL 2 TO OPERATE A POWER WINDOW CONTROL RELAY. THUS THE CURRENT INSIDE THE RELAY
FLOWS FROM TERMINAL 2 OF THE RELAY TERMINAL 1 TERMINAL 2 OF THE POWER WINDOW MOTOR TERMINAL 1 TERMINAL 4 OF THE RELAY TERMI-
NAL 3 TO GROUND. THE MOTOR TURNS TO ASCENT THE WINDOW. RELEASING THIS SW, THE ROTATION OF MOTOR IS STOPPED AND THE WINDOWS CAN STOP AT
WILL POINT.
(FOR THE MANUAL DOWNº OPERATION, CURRENT FLOWS IN THE REVERSE DIRECTION BECAUSE THE TERMINALS WHERE IT FLOW ARE CHANGED).
2. DRIVER'S WINDOW AUTO DOWNº OPERATION BY MASTER SW
ONCE THE AUTO DOWNº BUTTON OF THE MASTER SW IS PUSHED, THE CURRENT FLOW TERMINAL 9 OF THE POWER WINDOW CONTROL RELAY THROUGH TERMINAL 3
OF THE MASTER SW TERMINALS 8 AND 9 TO OPERATE THE RELAY. THUS THE CURRENT INSIDE THE POWER WINDOW CONTROL RELAY FLOWS FROM TERMINAL 2 OF
THE RELAY TERMINAL 4 TERMINAL 1 OF THE POWER WINDOW MOTOR TERMINAL 2 TERMINAL 1 OF THE RELAY TERMINAL 3 TO GROUND. THE
MOTOR CONTINUES THE ROTATION ENABLING TO DESCENT THE WINDOW.
THE WINDOW DESCENDS TO THE END POSITION. THE CURRENT WILL BE CUT OFF TO RELEASE THE AUTO DOWN FUNCTION BASED ON THE INCREASING CURRENT
BETWEEN TERMINAL 2 OF THE RELAY AND TERMINAL 1 IN RELAY.
3. DRIVER'S WINDOW AUTO DOWN RELEASE OPERATION BY MASTER SW
HOLDING THE MANUAL SW (DRIVER'S) ON UPº POSITION IN OPERATING AUTO DOWN. THE CURRENT FROM TERMINAL 3 OF THE MASTER SW PASSING TERMINAL 2
FLOWS TERMINAL 5 OF THE RELAY AND RELEASES THE AUTO DOWN FUNCTION IN THE POWER WINDOW CONTROL RELAY. RELEASING THE HAND FROM SW, WINDOW
STOPS AND CONTINUING ON TOUCHING SW. THE FUNCTION SWITCHES TO MANUAL UP OPERATION.
4. PASSENGER'S WINDOW UP OPERATION (MASTER SW) AND WINDOW LOCK SW OPERATION
HOLDING PASSENGER'S WINDOW SW (MASTER SW) ON UPº, THE CURRENT FLOWS FROM TERMINAL 3 OF THE MASTER SW PASSING TERMINAL 6 TO TERMINAL 3 OF THE
POWER WINDOW SW (PASSENGER'S) TERMINAL 4 TERMINAL 2 OF THE MOTOR TERMINAL 1 TERMINAL 9 OF THE POWER WINDOW SW TERMINAL 7 
TERMINAL 1 OF THE MASTER SW TERMINAL 4 TO GROUND. THE MOTOR RUNS TO ASCENT THE WINDOW. RELEASING THIS SW, THE ROTATION OF MOTOR IS
STOPPED AND WINDOW CAN STOP AT WILL PLACE. SWITCHING THE WINDOW LOCK SW IN LOCKº POSITION, THE CIRCUIT IS OPENED AND STOPPED THE MOTOR ROTA-
TION.
(FOR THE DOWN OPERATION, CURRENT FLOWS IN THE REVERSE DIRECTION BECAUSE THE TERMINALS WHERE IT FLOWS ARE CHANGED).
P 2 POWER WINDOW CONTROL RELAY
3-GROUND: ALWAYS CONTINUITY
2-GROUND: APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION
5-GROUND: APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION AND THE MASTER SW AT UP POSITION
8-GROUND: APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION AND THE MASTER SW AT AUTO DOWN POSITION
9-GROUND: APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION AND THE MASTER SW AT DOWN OR AUTO DOWN POSITION
P 4 POWER WINDOW MASTER SW
4-GROUND: ALWAYS CONTINUITY
3-GROUND: APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION
WINDOW LOCK SW
OPEN WITH THE WINDOW LOCK SW AT LOCK POSITION
: PARTS LOCATION
CODE SEE PAGE CODE SEE PAGE CODE SEE PAGE
P221P421P621
P321P521
: RELAY BLOCKS
CODE SEE PAGE RELAY BLOCK (RELAY BLOCK LOCATION)
116 R/B NO. 1 (INSTRUMENT PANEL LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODE SEE PAGE JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
3814 J/B NO. 3 AND COWL WIRE (INSTRUMENT PANEL LEFT SIDE)
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODE SEE PAGE JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
ID126 FRONT DOOR RH WIRE AND COWL WIRE (RIGHT KICK PANEL)
IH126 FRONT DOOR LH WIRE AND COWL WIRE (LEFT KICK PANEL)
: GROUND POINTS
CODE SEE PAGE GROUND POINT LOCATION
IC24 COWL LEFT
: SPLICE POINTS
CODE SEE PAGE WIRE HARNESS WITH SPLICE POINTS CODE SEE PAGE WIRE HARNESS WITH SPLICE POINTS
I 524 COWL WIREQ
R
S
T
U
V
W
X
SERVICE HINTS
SYSTEM OUTLINE

7
B
Q :Explains the system outline.
R :Indicates values or explain the function for reference during troubleshooting.
S :Indicates the reference page showing the position on the vehicle of the parts in the system circuit.
Example: Part P 4º (Power Window Master SW) is on page 21 of the manual.
* The letter in the code is from the first letter of the part, and the number indicates its order in
parts starting with the letter.
Example: P 4
HINTS:
Part is 4th in order
Power Window Master SW
Junction connector (code: J1 to J19) in this manual
include a short terminal which is connected to a
number of wire harnesses. Always perform inspec-
tion with the short terminal installed. (When instal-
ling the wire harnesses, the harnesses can be con-
nected to any position within the short terminal
grouping. Accordingly, in other vehicles, the same
position in the short terminal may be connected to
a wire harness from a different part.)
Wire harness sharing the same short terminal
grouping have the same color. T :Indicates the reference page showing the position on the vehicle of Relay Block Connectors in the system
circuit.
Example: Connector 1º is described on page 16 on this manual and is installed on the left side of the
instrument panel.
U :Indicates the reference page showing the position on the vehicle of J/B and Wire Harness in the system
circuit.
Example: Connector 3Bºconnects the Cowl Wire and J/B No. 3. It is described on page 14 of this manual,
and is installed on the instrument panel left side.
V :Indicates the reference page describing the wiring harness and wiring harness connector (the female wiring
harness is shown first, followed by the male wiring harness).
Example: Connector ID1ºconnects the front door RH wire (female) and cowl wire (male). It is described
on page 26 of this manual, and is installed on the right side kick panel.
W :Indicates the reference page showing the position of the ground points on the vehicle.
Example: Ground point ICº is described on page 24 of this manual and is installed on the cowl left side.
X :Indicates the reference page showing the position of the splice points on the vehicle.
Example: Splice point I 5º is on the Cowl Wire Harness and is described on page 24 of this manual.

10
C TROUBLESHOOTING
(a) Disconnect the battery terminal or wire so there is no
voltage between the check points.
(b) Contact the two leads of an ohmmeter to each of the
check point.
If the circuit has diodes, reverse the two leads and check
again.
When contacting the negative lead to the diode positive side
and the positive lead to the negative side, there should be
continuity.
When contacting the two leads in reverse, there should be
no continuity.
(c) Use the volt/ohmmeter with high impedance (10 kW/V
minimum) for troubleshooting of the electrical circuit.
CONTINUITY AND RESISTANCE CHECK VOLTAGE CHECK
(a) Establish conditions in which voltage is present at the
check point.
Example:

A- Ignition SW on

B- Ignition SW and SW 1 on

C- Ignition SW, SW 1 and Relay on (SW2 off)
(b) Using a voltmeter, connect the negative lead to a good
ground point or negative battery terminal, and the
positive lead to the connector or component terminal.
This check can be done with a test light instead of a
voltmeter.

11
C
(a) Remove the blown fuse and disconnect all loads of the
fuse.
(b) Connect a test light in place of the fuse.
(c) Establish conditions in which the test light comes on.
Example:
A - Ignition SW on
B - Ignition SW and SW 1 on
C - Ignition SW, SW 1 and Relay on (Connect the
Relay) and SW 2 off (or Disconnect SW 2)
(d) Disconnect and reconnect the connectors while watching
the test light.
The short lies between the connector where the test
light stays lit and the connector where the light goes
out.
(e) Find the exact location of the short by lightly shaking
the problem wire along the body.
(a) Do not open the cover or the case of the ECU unless
absolutely necessary. (If the IC terminals are touched,
the IC may be destroyed by static electricity.)
(b) When replacing the internal mechanism (ECU part) of
the digital meter, be careful that no part of your body
or clothing comes in contact with the terminals of
leads from the IC, etc. of the replacement part (spare
part).
CAUTION: FINDING A SHORT CIRCUIT
DISCONNECTION OF MALE AND FEMALE
CONNECTORS
To pull apart the connectors, pull on the connector itself, not
the wire harness.
HINT: Check to see what kind of connector you are
disconnecting before pulling apart.

16
ABBREVIATIONS D
ABBREVIATIONS
The follow abbreviations are used in this manual.
ABS = Anti-Lock Brake Systerm O/D = Overdrive
A/C = Air Conditioning PPS = Progressive Power Steering
ACIS = Acoustic Control Induction System R/B = Relay Block
A/T = Automatic Transmission RH = Right-Hand
COMB. = Combination SFI = Sequential Multiport Fuel Injection
ECU. = Electronic Control Unit SRS = Supplemental Restraint System
EGR = Exhaust Gas Recirculation SW = Switch
ESA = Electronic Spark Advance TEMP. = Temperature
EVAP = Evaporative Emission TRAC = Traction Control
J/B = Junction Block VSV = Vacuum Switching Valve
LH = Left-Hand w/ = With
M/T = Manual Transmission w/o = Without
* The titles given inside the components are the names of the terminals (terminal codes) and are not treated
as being abbreviations.

18
E
1. NORMALLY
OPEN
Open and
closes circuits,
thereby
stopping (1) or
allowing (2)
current flow.
RESISTOR
An electrical component with a
fixed resistance, placed in a circuit
to reduce voltage to a specific
value.
RESISTOR, TAPPED
A resistor which supplies two or
more different non adjustable
resistance values.
SENSOR (Thermistor)
A resistor which varies its
resistance with temperature.
SHORT PIN
Used to provide an unbroken
connection within a juction block.
SOLENOID
An electromagnetic coil which
forms a magnetic field when
current flows, to move a plunger,
etc.SWITCH, DOUBLE THROW
A switch which continuously
passes cureent through one set of
contacts or the other.
SWITCH,
IGNITION
A key operated switch with several
positions which allows various
circuits, particularly the primary
ignition circuit, to become
operational.
Wires are always
drawn as straight lines
on wiring diagrams.
Crossed wires (1)
without a black dot at
the junction are not
joined;
crossed wires (2) and
a black dot or
octagonal (
) mark at
the juction as spliced
(joined) connections. RELAY, DOUBLE THROW
A relay which passes current
through one set of contacts or the
other.
SENSOR, SPEED
Uses magnetic impulses to open
and close a switch to create a
signal for activation of other
components.TRANSISTOR
A solid state device typically used
as an electronic relay; stops or
passes current depending on the
voltage applied at base.º SWITCH, WIPER PARK
Automatically returns wipers to
the stop position when the wiper
switch is turned off. SWITCH, MANUALSPEAKER
An electromechanical device
which creates sound waves from
current flow.
2. NORMALLY
CLOSED
RESISTOR, VARIABLE or
RHEOSTAT
A controllable resistor with a
variable rate of resistance.
Also called a potentiometer or
rheostat.
2. NORMALLY
OPEN
RELAY
1. NORMALLY
CLOSED
Basically, an electrically
operated switch which
may be normally closed
(1) or open (2). Current
flow through a small
coil creates a magnetic
field which either opens
or closes an attached
switch.
(2) SPLICED
WIRES
(1) NOT
CONNECTED