Toyota Supra 2015 Wiring Diagram Manual page 88

SYSTEM OUTLINE
VOLTAGE IS ALWAYS APPLIED FROM THE MAIN FUSE, THROUGH THE HEADLIGHT RELAY (COIL SIDE) TO
TERMINAL 5 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN), TERMINAL 6 OF THE INTEGRATION RELAY,
TERMINAL 14 OF THE DIMMER SW, DIMMER RELAY (DAYTIME RUNNING LIGHT RELAY NO. 2) (COIL SIDE), TO
TERMINAL 17 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN). WHEN THE IGNITION SW IS TURNED ON, VOLTAGE
FROM THE GAUGE FUSE IS APPLIED TO TERMINAL 2 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN).
1. DAYTIME RUNNING LIGHT OPERATION
WHEN THE ENGINE STARTS, VOLTAGE FROM TERMINAL 'L' OF THE GENERATOR 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 DAYTIME RUNNING LIGHT SYSTEM DOES NOT OPERATE. WHEN THE PARKING BRAKE IS
RELEASED (PARKING BRAKE SW OFF), A SIGNAL IS OUTPUT FROM TERMINAL 1 OF THE PARKING BRAKE SW TO
TERMINAL 8 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN). THIS ACTIVATES THE DAYTIME RUNNING LIGHT
RELAY (MAIN), TURNING ON THE DIMMER RELAY (DAYTIME RUNNING LIGHT RELAY NO. 2). CURRENT ALSO FLOWS
FROM THE MAIN FUSE TO THE DIMMER RELAY (DAYTIME RUNNING LIGHT RELAY NO. 2) (POINT SIDE) → HEAD
(LH-UPR) FUSE → HEADLIGHT HI LH → HEADLIGHT HI RH → TERMINAL (A)5 OF THE DAYTIME RUNNING LIGHT
RELAY NO. 3 → TERMINAL (A)3 → GROUND, CAUSING THE HEADLIGHTS TO LIGHT UP AT APPROX. 20% OF THEIR
NORMAL BRIGHTNESS.
ONCE THE DAYTIME RUNNING LIGHT RELAY (MAIN) HAS BEEN ACTIVATED AND THE HEADLIGHTS LIGHT UP, THE
HEADLIGHTS REMAIN ON EVEN IF THE PARKING BRAKE LEVER IS ENGAGED AGAIN (PARKING BRAKE SW ON).
2. HEADLIGHT OPERATION
WHEN THE LIGHT CONTROL SW IS AT HEAD POSITION AND THE DIMMER SW AT LOW POSITION, CURRENT FLOWS
FROM THE HEADLIGHT RELAY (COIL SIDE) TO TERMINAL 3 OF THE INTEGRATION RELAY → TERMINAL 4 →
TERMINAL 13 OF THE LIGHT CONTROL SW → TERMINAL 11 → GROUND, ACTIVATING THE HEADLIGHT RELAY.
THIS CAUSES THE CURRENT TO FLOW FROM THE HEADLIGHT RELAY (POINT SIDE) TO THE HEAD LWR FUSE →
HEADLIGHT LO → GROUND, CAUSING THE HEADLIGHTS TO LIGHT UP AT NORMAL BRIGHTNESS. SIMUTANEOUSLY,
CURRENT FLOWS FROM THE DRL FUSE → DAYTIME RUNNING LIGHT RELAY NO. 3 (COIL SIDE) → GROUND,
ACTIVATING RELAY NO. 3.
WHEN THE DIMMER SW IS AT HIGH POSITION, TERMINAL 12 OF THE DIMMER SW OUTPUTS A SIGNAL TO
TERMINAL 16 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN) TO ACTIVATE IT. THIS TURNS ON DIMMER RELAY
(DAYTIME RUNNING LIGHT RELAY NO. 2). SO CURRENT FLOWS FROM THE DIMMER RELAY (DAYTIME RUNNING
LIGHT RELAY NO. 2) (POINT SIDE) TO THE HEAD (LH-UPR) FUSE → HEADLIGHT HI LH → DAYTIME RUNNING LIGHT
NO. 3 (POINT SIDE) → GROUND, AND FROM THE HEAD (RH-UPR) FUSE → DAYTIME RUNNING LIGHT RELAY NO. 3
(POINT SIDE) → HEADLIGHT HI RH → DAYTIME RUNNING LIGHT RELAY NO. 3 (POINT SIDE) → GROUND, CAUSING
THE HEADLIGHTS TO OPERATE AT HI.
WHEN THE DIMMER SW IS AT FLASH POSITION, CURRENT FROM THE HEADLIGHT RELAY (COIL SIDE) FLOWS TO
TERMINAL 14 OF THE DIMMER SW → TERMINAL 9 → GROUND, ACTIVATING THE RELAY. SIMULTANEOUSLY,
CURRENT FROM THE HEADLIGHT RELAY (POINT SIDE) FLOWS TO HEADLIGHT LO, LIGHTING UP HEADLIGHT LO
AND ACTIVATING DAYTIME RUNNING LIGHT RELAY NO. 3. THEN TERMINAL 12 OF THE DIMMER SW OUTPUTS A
SIGNAL TO TERMINAL 16 OF THE DAYTIME RUNNING LIGHT RELAY (MAIN), ACTIVATING THE DAYTIME RUNNING
LIGHT RELAY (MAIN) SO THAT CURRNET FLOWS TO HEADLIGHT HI LIKE IT DOES FOR HIGH POSITION. THIS
CAUSES ALL HEADLIGHTS TO LIGHT UP.
SERVICE HINTS
D6 DAYTIME RUNNING LIGHT RELAY (MAIN)
15-GROUND : ALWAYS APPROX. 12 VOLTS
2-GROUND : APPROX. 12 VOLTS WITH TEH IGNITION SW AT ON POSITION
13-GROUND : ALWAYS CONTINUITY
5-GROUND : APPROX. 12 VOLTS WITH THE DAYTIME RUNNING LIGHT SYSTEM
DOES NOT OPERATE OR THE LIGHT CONTROL SW AT OFF OR TAIL POSITION
(WHEN THE CONNECTOR IS DISCONNECTED, ALWAYS APPROX. 12 VOLTS)
8-GROUND : CONTINUITY WITH THE PARKING BRAKE LEVER RELEASED
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