2004 YAMAHA YZF-R1SC brake light

8-36
YESNO

Clean the battery
terminals.

Recharge or re-
place the battery.
EAS00749
3. Main switch

Check the main switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the main switch OK?
YESNO
Replace the main
switch.
YESNO 1. Horn switch

Check the horn switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the horn switch OK?
Replace the left han-
dlebar switch.
EAS00796
CHECKING THE SIGNALING SYSTEM
1. The horn fails to sound.
EAS00795
4. Wiring

Check the entire signaling system’s wiring.
Refer to “CIRCUIT DIAGRAM”.

Is the signaling system’s wiring properly
connected and without defects?
YESNO
Properly connect or
repair the signaling
system’s wiring.
Check the condition
of each of the signal-
ing system’s circuits.
Refer to “CHECK-
ING THE LIGHTING
SYSTEM”.
SIGNALING SYSTEMELEC
NOTE:
YESNO
1. Backup, main, ignition, signal and park
fuses

Check the backup, main, ignition, signal and
park fuses for continuity.
Refer to “CHECKING THE FUSES” in chap-
ter 3.

Are the backup, main, ignition, signal and
park fuses OK?
Replace the fuse(s).
2. Battery

Check the condition of the battery.
Refer to “CHECKING AND CHARGING
THE BATTERY” in chapter 3.
Minimum open-circuit voltage
12.8 V or more at 20C (68F)

Is the battery OK?
EAS00739EAS00794
TROUBLESHOOTING

Any of the following fail to light: turn sig-
nal light, brake light or an indicator light.

The horn fails to sound.
Check:
1. backup, main, ignition, signal, and park
fuses
2. battery
3. main switch
4. wiring connections
(of the entire signaling system)

Before troubleshooting, remove the following
part(s):
1. seat
2. fuel tank
3. side cowlings

Troubleshoot with the following special tool(s).
Pocket tester
90890-03112, YU-3112
EAS00738
ProCarManuals.com

8-37
SIGNALING SYSTEMELEC
YESNO 1. Tail / brake light bulb and socket

Check the tail / brake light bulb and socket for
continuity.
Refer to “CHECKING THE BULBS AND
BULB SOCKETS”.

Are the tail / brake light bulb and socket OK?
Replace the tail /
brake light bulb,
socket or both.
EAS007972. The tail / brake light fails to come on.
YESNO 2. Brake light switches

Check the brake light switches for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the brake light switch OK?
Replace the brake
light switch.
3. Voltage

Connect the pocket tester (DC 20 V) to the
tail / brake light coupler (wire harness side)
as shown.
Positive tester probe
yellow
Negative tester probe
black
1
2

Turn the main switch to “ON”.

Pull in the brake lever or push down on the
brake pedal.

Measure the voltage (DC 12 V) of yellow
on the tail / brake light coupler (wire harness
side).

Is the voltage within specification?
1
YESNO 2. Voltage

Connect the pocket tester (DC 20 V) to the
horn connector at the horn terminal as
shown.
The wiring circuit
from the main switch
to the horn connec-
tor is faulty and must
be repaired. Positive tester probe
black / white
Negative tester probe
ground
1

Turn the main switch to “ON”.

Push the horn switch.

Measure the voltage (DC 12 V) of
black / white at the horn terminal.

Is the voltage within specification?
NOYES 3. Horn

Disconnect the black connector at the horn
terminal.

Connect a jumper lead to the horn termi-
nal and ground the jumper lead.

Turn the main switch to “ON”.

Push the horn switch.

Does the horn sound?
The horn is OK.
1
Replace the horn.
ProCarManuals.com

8-38
SIGNALING SYSTEMELEC
NO
YESNO
The wiring circuit
from the main switch
to the tail / brake light
coupler is faulty and
must be repaired.
This circuit is OK.
YES 1. Turn signal indicator light (LEDs)

Check the turn signal indicator light for conti-
nuity.
Refer to “CHECKING THE LEDs”.

Are the turn signal indicator light OK?
Replace the meter
assembly.
EAS00799
3. The turn signal / position light, turn signal in-
dicator light or both fail to blink.
YES
2. Turn signal switch

Check the turn signal switch for continuity.
Refer to “CHECKING THE SWITCHES”.

Is the turn signal switch OK?
Replace the left han-
dlebar switch.
3. Voltage

Connect the pocket tester (DC 20 V) to the
turn signal relay coupler (wire harness side)
as shown.
Positive tester probe
brown
Negative tester probe
ground
1

Turn the main switch to “ON”.

Measure the voltage (DC 12 V) on brown
at the turn signal relay coupler (wire harness
side).

Is the voltage within specification?
1
YESNO
The wiring circuit
from the main switch
to the turn signal
relay coupler is faulty
and must be re-
paired.
YESNO 4. Voltage

Connect the pocket tester (DC 20 V) to the
turn signal relay coupler (wire harness side)
as shown.
The turn signal relay
is faulty and must be
replaced. Positive tester probe
brown / white
Negative tester probe
ground
1

Turn the main switch to “ON”.

Measure the voltage (DC 12 V) on
brown / white at the turn signal relay cou-
pler (wire harness side).

Is the voltage within specification?
1
NO
ProCarManuals.com

9-6
FAULTY LIGHTING OR SIGNALING SYSTEM
TRBL
SHTG
TURN SIGNAL DOES NOT COME ON

Faulty turn signal switch

Faulty turn signal relay

Burnt-out turn signal bulb

Incorrect connection

Damaged or faulty wire harness

Improperly grounded circuit

Faulty battery

Blown, damaged or incorrect fuse
TURN SIGNAL BLINKS SLOWLY

Faulty turn signal relay

Faulty main switch

Faulty turn signal switch

Incorrect turn signal bulb
TURN SIGNAL REMAINS LIT

Faulty turn signal relay

Burnt-out turn signal bulb
TURN SIGNAL BLINKS QUICKLY

Incorrect turn signal bulb

Faulty turn signal relay

Burnt-out turn signal bulb
HORN DOES NOT SOUND

Improperly adjusted horn

Damaged or faulty horn

Faulty main switch

Faulty horn switch

Faulty battery

Blown, damaged or incorrect fuse

Faulty wire harness
EAS00866
FAULTY LIGHTING OR SIGNALING SYSTEM
HEADLIGHT DOES NOT COME ON

Wrong headlight bulb

Too many electrical accessories

Hard charging

Incorrect connection

Improperly grounded circuit

Poor contacts (main or light switch)

Burnt-out headlight bulb
HEADLIGHT BULB BURNT OUT

Wrong headlight bulb

Faulty battery

Faulty rectifier / regulator

Improperly grounded circuit

Faulty main switch

Faulty light switch

Headlight bulb life expired
TAIL / BRAKE LIGHT DOES NOT COME ON

Too many electrical accessories

Incorrect connection
TAIL / BRAKE LIGHT BULB BURNT OUT

Faulty battery

Incorrectly adjusted rear brake light switch
ProCarManuals.com

59Clutch switch
60Turn signal switch
61Horn
62Front turn signal / position light (left)
63Front turn signal / position light (right)
64Rear turn signal light (left)
65Rear turn signal light (right)
66Headlight
67Auxiliary light
68License plate light
69Rear brake light switch
70Tail / brake light
71Headlight relay (on / off)
72Headlight relay (dimmer)
73Fuse (ignition)
74Fuse (signal)
75Fuse (headlight)
76Radiator fan motor relay
77Fuse (radiator fan motor left)
78Fuse (radiator fan motor light)
79Radiator fan motor 2
80Radiator fan motor 1
81Ground
COLOR CODE
B Black. . . . .
Br Brown. . . .
Ch Chocolate. . .
Dg Dark green. . .
G Green. . . .
Gy Gray. . .
L Blue. . . . .
Lg Light green. . . .
O Orange. . . .
P Pink. . . . .
R Red. . . . .
Sb Sky blue. . . .
W White. . . .
Y Yellow. . . . .
B / G Black / Green. .
B / L Black / Blue. . .
B / R Black / Red. .
B / W Black / White. .
B / Y Black / Yellow. .
Br / G Brown / Green.
Br / L Brown / Blue. .
Br / R Brown / Red. .
Br / W Brown / White.
G / B Green / Black. .
G / R Green / Red. .
G / W Green / White. . G / Y Green / Yellow. .
Gy / B Gray / Black.
Gy / G Gray / Green.
Gy / R Gray / Red.
L / B Blue / Black. . .
L / R Blue / Red. .
L / W Blue / White. .
L / Y Blue / Yellow. . .
O / B Orange / Black. .
O / G Orange / Green. .
P / W Pink / White. .
R / B Red / Black. .
R / G Red / Green. .
R / L Red / Blue. .
R / W Red / White. .
R / Y Red / Yellow. .
Sb / W Sky blue / White.
W / B White / Black. .
W / R White / Red. .
W / Y White / Yellow. .
Y / B Yellow / Black. .
Y / G Yellow / Green. .
Y / L Yellow / Blue. . .
Y / R Yellow / Red. .
Y / W Yellow / White. .
YZF-R1S / YZF-R1SC WIRING DIAGRAM
1Main switch
2A.C. magneto
3Rectifier / regulator
4Fuse (main)
5Fuse (backup)
6Battery
7Fuse (fuel injection)
8Starter relay
9Starter motor
10Starting circuit cut-off relay
11Neutral switch
12Sidestand switch
13Fuel pump
14E.C.U
15Ignition coil #1
16Ignition coil #2
17Ignition coil #3
18Ignition coil #4
19Spark plug
20Injector #1
21Injector #2
22Injector #3
23Injector #4
24Air induction system solenoid
25Sub-throttle position sensor
26EXUP servo motor
27Speed sensor
28Coolant temperature sensor
29Intake air temperature sensor
30Option switch
31Crankshaft position sensor
32Throttle position sensor
33Intake air pressure sensor
34Atmospheric pressure sensor
35Cylinder identification sensor
36Lean angle cut-off switch
37Meter assembly
38Fuel level warning light
39Oil level warning light
40Neutral indicator light
41Tacho meter
42Shift timing indicator light
43Multi function meter
44Engine trouble warning light
45Coolant temperature indicator light
46Hi beam indicator light
47Turn signal indicator light (left)
48Turn signal indicator light (light)
49Meter light
50Oil level switch
51Right handlebar switch
52Front brake light switch
53Engine stop switch
54Start switch
55Turn signal relay
56Left handlebar switch
57Dimmer switch
58Horn switch
ProCarManuals.com