Toyota COROLLA 2004 Electrical Wiring Diagram - glossary of terms and symbols

E GLOSSARY OF TERMS AND SYMBOLS

FUSIBLE LINK

BATTERY

Stores chemical energy and
converts it into electrical energy.
Provides DC current for the auto’s
various electrical circuits.

CAPACITOR (Condenser)

A small holding unit for temporary
storage of electrical voltage.

CIGARETTE LIGHTER

An electric resistance heating
element.

CIRCUIT BREAKER

Basically a reusable fuse, a circuit
breaker will heat and open if too
much current flows through it.
Some units automatically reset when
cool, others must be manually reset.

DIODE

A semiconductor which allows
current flow in only one direction.

1. SINGLE
FILAMENT

2. DOUBLE
FILAMENT

GROUND

The point at which wiring attaches to
the Body, thereby providing a return
path for an electrical circuit; without a
ground, current cannot flow.

HEADLIGHTS

Current flow causes a headlight
filament to heat up and emit light. A
headlight may have either a single
(1) filament or a double (2) filament

HORN

An electric device which sounds a
loud audible signal.

IGNITION COIL

Converts low–voltage DC current
into high–voltage ignition current for
firing the spark plugs.

(for Medium Current Fuse)

(for High Current Fuse or
Fusible Link)

DIODE, ZENER

A diode which allows current flow in one
direction but blocks reverse flow only up
to a specific voltage. Above that potential,
it passes the excess voltage. This acts as
a simple voltage regulator.

PHOTODIODE

The photodiode is a semiconductor
which controls the current flow
according to the amount of light.

DISTRIBUTOR, IIA

Channels high–voltage current from
the ignition coil to the individual
spark plugs.

FUSE

A thin metal strip which burns through
when too much current flows through it,
thereby stopping current flow and
protecting a circuit from damage.

FUSIBLE LINK

A heavy–gauge wire placed in high
amperage circuits which burns through on
overloads, thereby protecting the circuit.
The numbers indicate the crosssection
surface area of the wires.

FUEL

M

LIGHT

Current flow through a filament
causes the filament to heat up and
emit light.

LED (LIGHT EMITTING DIODE)

Upon current flow, these diodes emit
light without producing the heat of a
comparable light.

METER, ANALOG

Current flow activates a magnetic
coil which causes a needle to move,
thereby providing a relative display
against a background calibration.

METER, DIGITAL

Current flow activates one or many
LED’s, LCD’s, or fluorescent
displays, which provide a relative or
digital display.

MOTOR

A power unit which converts
electrical energy into mechanical
energy, especially rotary motion.

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2004 COROLLA (EWD533U)

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RELAY

1. NORMALLY
CLOSED

2. NORMALLY
OPEN

RELAY, DOUBLE THROW

RESISTOR

RESISTOR, TAPPED

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.

A relay which passes current
through one set of contacts or the
other.

An electrical component with a fixed
resistance, placed in a circuit to
reduce voltage to a specific value.

A resistor which supplies two or
more different non adjustable
resistance values.

SPEAKER

An electromechanical device which
creates sound waves from current
flow.

SWITCH, MANUAL

1. NORMALLY
OPEN

2. NORMALLY
CLOSED

SWITCH, DOUBLE THROW

A switch which continuously passes
current 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.

Opens and closes
circuits, thereby
stopping (1) or
allowing (2) current
flow.

(Reed Switch Type)

RESISTOR, VARIABLE or RHEOSTAT

A controllable resistor with a variable
rate of resistance.
Also called a potentiometer or
rheostat.

SENSOR (Thermistor)

A resistor which varies its resistance
with temperature.

SENSOR, SPEED

Uses magnetic impulses to open
and close a switch to create a signal
for activation of other components.

SHORT PIN

Used to provide an unbroken
connection within a junction block.

SOLENOID

An electromagnetic coil which forms
a magnetic field when current flows,
to move a plunger, etc.

SWITCH, WIPER PARK

Automatically returns wipers to the
stop position when the wiper switch
is turned off.

TRANSISTOR

A solidstate device typically used as
an electronic relay; stops or passes
current depending on the voltage
applied at ”base”.

WIRES

(1) NOT
CONNECTED

(2) SPLICED

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) with a
black dot or octagonal ( )
mark at the junction are
spliced (joined)
connections.

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2004 COROLLA (EWD533U)