headlights TOYOTA CAMRY 1994 XV10 / 4.G Wiring Diagrams Workshop Manual

METER, ANALOG
Current flow activates a magnetic
coil which causes a needle to
move, thereby providing a relative
display against a background
calibration. LED (LIGHT EMITTING DIODE)
Upon current flow, these diodes
emit light without producing the
heat of a comparable light. IGNITION COIL
Converts low±voltage DC current
into high±voltage ignition current
for firing the spark plugs. 1. SINGLE
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.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. 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.
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.
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.
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 cross±
section surface area of the wires.HORN
An electric device which sounds a
loud audible signal.
LIGHT
Current flow through a filament
causes the filament to heat up
and emit light.
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. CIGARETTE LIGHTER
An electric resistance heating
element.
DISTRIBUTOR, IIA
Channels high±voltage current
from the ignition coil to the
individual spark plugs.2. DOUBLE
FILAMENT HEADLIGHTS
FUEL
(for High Current Fuse or
Fusible Link.)
(for Medium Current Fuse)
M
16
GLOSSARY OF TERMS AND SYMBOLS

88
ENGINE CONTROL (5S±FE)
THIS SYSTEM UTILIZES AN ENGINE CONTROL MODULE (ENGINE ECU (M/T), ENGINE AND ELECTRONIC CONTROLLED
TRANSMISSION ECU (A/T)) AND MAINTAINS OVERALL CONTROL OF THE ENGINE, TRANSMISSION AND SO ON. AN OUTLINE OF THE
ENGINE CONTROL IS EXPLAINED HERE.
1. INPUT SIGNALS
(1) ENGINE COOLANT TEMP. (WATER TEMP.) SIGNAL SYSTEM
THE ENGINE COOLANT TEMP. SENSOR (EFI WATER TEMP. SENSOR) DETECTS THE ENGINE COOLANT TEMP. AND HAS A
BUILT±IN THERMISTOR WITH A RESISTANCE WHICH VARIES ACCORDING TO THE ENGINE COOLANT TEMP. (WATER TEMP.)
THUS THE ENGINE COOLANT TEMP. (WATER TEMP.) IS INPUT IN THE FORM OF A CONTROL SIGNAL TO TERMINAL THW OF
THE ENGINE CONTROL MODULE (ECU).
(2) INTAKE AIR TEMP. SIGNAL SYSTEM
THE INTAKE AIR TEMP. SENSOR (IN±AIR TEMP. SENSOR) IS DETECTS THE INTAKE AIR TEMP., WHICH IS INPUT AS A
CONTROL SIGNAL TO TERMINAL THA OF THE ENGINE CONTROL MODULE (ECU).
(3) OXYGEN SENSOR SIGNAL SYSTEM
THE OXYGEN DENSITY IN THE EXHAUST GASES IS DETECTED AND INPUT AS A CONTROL SIGNAL TO TERMINAL OX1 AND
OX2 OF THE ENGINE CONTROL MODULE (ECU).
(4) RPM SIGNAL SYSTEM
CRANKSHAFT POSITION AND ENGINE RPM ARE DETECTED BY THE PICK±UP COIL INSTALLED INSIDE THE DISTRIBUTOR.
CRANKSHAFT POSITION IS INPUT AS A CONTROL SIGNAL TO TERMINALS G+ AND G2 (CALIFORNIA), OF THE ENGINE
CONTROL MODULE (ECU), AND RPM IS INPUT TO TERMINAL NE+.
(5) THROTTLE SIGNAL SYSTEM
THE THROTTLE POSITION SENSOR DETECTS THE THROTTLE VALVE OPENING ANGLE, WHICH IS INPUT AS A CONTROL
SIGNAL TO TERMINAL VTA OF THE ENGINE CONTROL MODULE (ECU), OR WHEN THE VALVE IS FULLY CLOSED, TO
TERMINAL IDL
(6) VEHICLE SPEED SIGNAL SYSTEM
THE VEHICLE SPEED SENSOR (SPEED SENSOR), INSTALLED INSIDE THE COMBINATION METER, DETECTS THE VEHICLE
SPEED AND INPUTS A CONTROL SIGNAL TO TERMINAL SPD OF THE ENGINE CONTROL MODULE (ECU).
(7) PARK/NEUTRAL POSITION SW (NEUTRAL START SW) SIGNAL SYSTEM (A/T)
THE PARK/NEUTRAL POSITION SW (NEUTRAL START SW) DETECTS WHETHER THE SHIFT POSITION ARE IN NEUTRAL AND
PARKING OR NOT, AND INPUTS A CONTROL SIGNAL TO TERMINAL NSW OF THE ENGINE CONTROL MODULE (ECU).
(8) A/C SW SIGNAL SYSTEM
THE A/C AMPLIFIER INPUTS THE A/C OPERATIONS TO TARMINAL ACA OF THE ENGINE CONTROL MODULE (ECU) AS A
CONTROL SIGNAL.
(9) BATTERY SIGNAL CIRCUIT
VOLTAGE IS CONSTANTLY APPLIED TO TERMINAL BATT OF THE ENGINE CONTROL MODULE (ECU). WHEN THE IGNITION SW
TURNED ON, THE VOLTAGE FOR ENGINE CONTROL MODULE (ECU) START±UP POWER SUPPLY IS APPLIED TO TERMINALS
+B AND +B1 OF ENGINE CONTROL MODULE (ECU) VIA EFI MAIN RELAY. THE CURRENT FLOWING THROUGH THE IGN FUSE
FLOWS TO TERMINAL IGSW OF THE ENGINE CONTROL MODULE (ECU).
(10) INTAKE AIR VOLUME SIGNAL SYSTEM
INTAKE AIR VOLUME IS DETECTED BY THE MANIFOLD ABSOLUTE PRESSURE SENSOR (VACUUM SENSOR) (FOR MANIFOLD
PRESSURE) AND IS INPUT AS A CONTROL SIGNAL TO TERMINAL PIM OF THE ENGINE CONTROL MODULE (ECU).
(11) STA SIGNAL CIRCUIT
TO CONFIRM WHETHER THE ENGINE IS CRANKING, THE VOLTAGE APPLIED TO THE STARTER MOTOR DURING CRANKING IS
DETECTED AND THE SIGNAL IS INPUT INTO TERMINAL STA OF THE ENGINE CONTROL MODULE (ECU) AS A CONTROL
SIGNAL.
(12) ENGINE KNOCK SIGNAL CIRCUIT
ENGINE KNOCKING IS DETECTED BY KNOCK SENSOR AND THE SIGNAL IS INPUT INTO TERMINAL KNK AS A CONTROL
SIGNAL.
(13) ELECTRICAL LOAD SIGNAL SYSTEM
THE SIGNAL WHEN SYSTEMS SUCH AS THE REAR WINDOW DEFOGGER, HEADLIGHTS, ETC. WHICH CAUSE A HIGH
ELECTRICAL BURDEN ARE ON IS INPUT TO TERMINAL ELS AS A CONTROL SIGNAL.
SYSTEM OUTLINE

109
CURRENT FROM THE BATTERY IS ALWAYS FLOWING FROM THE FL MAIN " HEADLIGHT RELAY (COIL SIDE) " TERMINAL 5 OF THE
DAYTIME RUNNING LIGHT RELAY (MAIN) AND TERMINAL 14 OF THE DIMMER SW, HEADLIGHT RELAY (COIL SIDE) " TERMINAL 3 OF
THE INTEGRATION RELAY " TERMINAL 4 " TERMINAL 13 OF THE LIGHT CONTROL SW, FL MAIN " DAYTIME RUNNING LIGHT
RELAY NO. 2 (COIL SIDE) " TERMINAL 17 OF THE DAYTIME RUNNING LIGHT RELAY.
1. DAYTIME RUNNING LIGHT OPERATION
WHEN THE ENGINE IS STARTED, VOLTAGE GENERATED AT TERMINAL L OF THE GENERATOR (ALTERNATOR) IS APPLIED TO
TERMINAL 11 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN).
IF THE PARKING BRAKE LEVER IS PULLED UP (PARKING BRAKE SW ON) AT THIS TIME, THE RELAY IS NOT ENERGIZED, SO THE
DAYTIME RUNNING LIGHT SYSTEM DOES NOT OPERATE. IF THE PARKING BRAKE LEVER IS RELEASED (PARKING BRAKE LEVER
SW OFF), THE SIGNAL IS INPUT TO TERMINAL 8 OF THE RELAY. THIS ACTIVATES THE RELAY ALSO, CURRENT FROM FL MAIN
FLOWES TO DAYTIME RUNNING LIGHT RELAY NO. 2 (POINT SIDE) " HEAD (UPR±LH) FUSE " TERMINAL 1 OF THE HEAD LH±HI "
TERMINAL 2 " TERMINAL 2 OF THE HEAD RH±HI " TERMINAL 1 " TERMINAL 4 OF THE DAYTIME RUNNING LIGHT RELAY NO. 3 "
TERMINAL 2 " TO GROUND, SO BOTH TAIL AND HEADLIGHT UP.
THIS IS HOW THE DAYTIME RUNNING LIGHT SYSTEM OPERATES. ONCE THE DAYTIME RUNNING LIGHT SYSTEM OPERATES AND
HEAD HAVE LIGHT UP, HEAD REMAIN ON EVEN IF THE PARKING BRAKE LEVER IS PULLED UP (PARKING BRAKE SW ON).
EVEN IF THE ENGINE STALLS WITH THE IGNITION SW ON AND THERE IS NO VOLTAGE FROM TERMINAL L OF THE GENERATOR
(ALTERNATOR), HEAD REMAIN ON. IF THE IGNITION SW IS THEN TURNED OFF, AND HEAD ARE TURNED OFF.
IF THE ENGINE IS STARTED WHILE THE PARKING BRAKE LEVER IS RELEASED (PARKING BRAKE SW OFF), THE DAYTIME RUNNING
LIGHT SYSTEM OPERATES AND TAIL, HEADLIGHT UP AS THE ENGINE STARTS.
2. HEADLIGHT OPERATION
*(WHEN THE LIGHT CONTROL SW AT THE HEAD POSITION)
WHEN THE LIGHT CONTROL SW IS SET TO HEAD POSITION, THE CURRENT FLOWING TO THE HEADLIGHT RELAY (COIL SIDE)
FLOWS TO TERMINAL 3 OF THE INTEGRATION RELAY " TERMINAL 4 " TERMINAL 13 OF THE LIGHT CONTROL SW " TERMINAL 11
" GROUND, TURNING THE HEADLIGHT RELAY ON.
THIS CAUSES THE CURRENT FLOWING TO THE HEADLIGHT RELAY (POINT SIDE) " DRL FUSE " DAYTIME RUNNING LIGHT RELAY
NO. 3 (COIL SIDE) AND DAYTIME RUNNING LIGHT RELAY NO. 4 (COIL SIDE) " GROUND, TURNING THE DAYTIME RUNNING LIGHT
RELAY NO. 3 AND NO. 4 ON. ALSO, CURRENT FROM THE HEADLIGHT RELAY (POINT SIDE) TO HEAD (LWR) FUSES " TERMINAL 1
OF THE HEADLIGHTS (LO) " TERMINAL 2 " GROUND, SO THE HEADLIGHTS (LO) LIGHT UP.
*(DIMMER SW AT FLASH POSITION)
WHEN THE DIMMER SW IS SET TO FLASH POSITION, CURRENT FLOWS FROM HEADLIGHT RELAY (COIL SIDE) " TERMINAL 14 OF
THE DIMMER SW " TERMINAL 9 " GROUND, TURNING THE HEADLIGHT RELAY ON. AT THE SAME TIME, SIGNALS ARE OUTPUT
FROM TERMINAL 12 AND TERMINAL 14 OF THE DIMMER SW TO TERMINAL 16 AND TERMINAL 5 OF THE DAYTIME RUNNING LIGHT
RELAY (MAIN), ACTIVATING THE DAYTIME RUNNING LIGHT RELAY (MAIN) AND ALSO THE DAYTIME RUNNING LIGHT RELAY NO. 2.
WHEN THE HEADLIGHT RELAY AND DAYTIME RUNNING LIGHT RELAY (MAIN) ARE ACTIVATED, THE HEADLIGHTS (LO AND HI) THEN
LIGHT UP.
*(DIMMER SW AT HIGH POSITION)
WHEN THE LIGHT CONTROL SW IS SET TO HEAD POSITION, A SIGNAL IS OUTPUT FROM TERMINAL 13 OF THE LIGHT CONTROL SW
" TERMINAL 4 OF THE INTEGRATION RELAY " TERMINAL 3 " TERMINAL 5 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN).
WHEN THE DIMMER SW IS SET TO HIGH POSITION, A SIGNAL IS OUTPUT FROM TERMINAL 12 OF THE DIMMER SW TO TERMINAL 16
OF THE DAYTIME RUNNING LIGHT RELAY (MAIN). THESE SIGNALS ACTIVATE DAYTIME RUNNING LIGHT RELAY NO. 2, SO CURRENT
FLOWS FROM DAYTIME RUNNING LIGHT RELAY NO. 2 (POINT SIDE) " HEAD (UPR±LH) FUSE " TERMINAL 1 OF THE HEADLIGHT
LH±HI " TERMINAL 2 " DAYTIME RUNNING LIGHT RELAY NO. 4 (POINT SIDE) " GROUND, AND CURRENT ALSO SIMUTANEOUSLY
FLOWS FROM HEAD (UPR±RH) FUSE " DAYTIME RUNNING LIGHT RELAY NO. 3 (POINT SIDE) " TERMINAL 1 OF THE HEADLIGHT
RH±HI " TERMINAL 2 " DAYTIME RUNNING LIGHT RELAY NO. 4 (POINT SIDE), CAUSING THE HEADLIGHTS (HI SIDE) TO LIGHT UP.
D 4 DAYTIME RUNNING LIGHT RELAY (MAIN)
2±GROUND : APPROX. 12 VOLTS WITH THE IGNITION SW AT ON POSITION
15±GROUND : ALWAYS APPROX. 12 VOLTS
8±GROUND : CONTINUITY WITH THE PARKING BRAKE LEVER PULLED UP (PARKING BRAKE SW ON)
13±GROUND : ALWAYS CONTINUITY
SYSTEM OUTLINE
SERVICE HINTS