Toyota 2003 Prius, Manual

Page: 106 / 307

2003 PRIUS (EWD493U)
105
With the ignition SW turned on, the current flows to TERMINAL 15 of the body ECU through GAUGE fuse.
Voltage is applied at all times to TERMINAL (B) 11 of the body ECU through the TAIL relay coil side, and to TERMINAL (B) 2
through the HEAD relay coil side (w/o daytime running light) or through the daytime running light relay (w/ daytime running
light).
1. NORMAL LIGHTING OPERATION
<Turn taillight on>
With the light control SW turned to TAIL position, a signal is input into TERMINAL (B) 18 of the body ECU. Due to this signal,
the current flowing to TERMINAL (B) 11 of the body ECU flows to TERMINAL (B) 18 to TERMINAL 14 of the light control SW
to TERMINAL 16 to GROUND, and taillight relay causes taillights to turn on.
<Turn headlight on>
With the light control SW turned to HEAD position, a signal is input into TERMINALS (B) 17 and (B) 18 of the body ECU. Due
to this signal, the current flowing to TERMINAL (B) 2 of the body ECU flows to TERMINAL (B) 17 to TERMINAL 13 of the
light control SW to TERMINAL 16 to GROUND in the headlight circuit, and causes taillight and HEAD relay to turn the lights
on. The taillight circuit is same as above.
2. LIGHT AUTO TURN OFF OPERATION
With light on and ignition SW turned off (Input signal goes to TERMINAL 15 of the body ECU), when the driver’s door is
opened (Input signal goes to TERMINAL 3 of the body ECU), the ECU operates and the current is cut off which flows from
TERMINAL (B) 11 of the body ECU to TERMINAL (B) 18 in taillight circuit and from TERMINAL (B) 2 to TERMINAL (B) 17 in
headlight circuit.
As a result, all lights are turned off automatically.
HEAD RELAY
2–1 : Closed with the light control SW at HEAD position or the dimmer SW at FLASH position
Closed with the engine running and the parking brake pedal released (Parking brake SW off) [w/ daytime running light]
TAIL RELAY
3–5 : Closed with the light control SW at TAIL or HEAD position
D6 DOOR COURTESY SW LH
1–GROUND : Continuity with the front LH door open
B9 (B) BODY ECU
15–GROUND : Approx. 12 volts with the ignition SW at ON position
3–GROUND : Continuity with the front LH door open
(B) 9–GROUND : Always approx. 12 volts
(B) 1–GROUND : Always continuity
(B)17–GROUND : Continuity with the light control SW at HEAD position
(B)18–GROUND : Continuity with the light control SW at TAIL or HEAD position
: PARTS LOCATION
Code See Page Code See Page Code See Page
B9 B
36
F13 D
34
J20
37
C13 36 F18 38 J24 A 37
D3 36 J11 37 J25 B 37
D6
38
J12 A
37
J27
37
F11 B 34 J13 B 37 U1 37
F12 C 34 J17 37
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: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
Code See Page Junction Block and Wire Harness (Connector Location)
1B
27 Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)
1F
27 Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)
2C
30 Instrument Panel Wire and Instrument Panel J/B (Cowl Side Panel LH)
2D
30 Instrument Panel Wire and Instrument Panel J/B (Cowl Side Panel LH)
2H 31 Engine Room Main Wire and Instrument Panel J/B (Cowl Side Panel LH)
2K
31
Cowl Wire and Instrument Panel J/B (Cowl Side Panel LH)
SYSTEM OUTLINE
SERVICE HINTS