Checking The Signaling System - Yamaha 2004 YP400 Service Manual

EAS00796

CHECKING THE SIGNALING SYSTEM

1. The horn fails to sound.
1. Horn switch
• Check the horn switch for continuity.
Refer to "CHECKING THE SWITCHES".
• Is the horn switch OK?
YES
2. Voltage
• Connect the pocket tester (DC 20 V) to the
horn coupler as shown.
Positive tester probe → brown 1
Negative tester probe → ground
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) of brown at
the horn coupler.
• Is the voltage within specification?
YES
NO
Replace the left han-
dlebar switch.
1
Br
P
NO
The wiring circuit
from the main switch
to the horn coupler is
faulty and must be
repaired.
SIGNALING SYSTEM
3. Horn
• Disconnect the horn coupler at the horn.
• Connect a jumper lead 1 to the brown ter-
minal in the horn coupler and the horn ter-
minal.
• Connect a jumper lead 2 to the horn ter-
minal and ground.
• Set the main switch to "ON".
• Does the horn sound?
The wiring
from the horn coupler
to the horn switch
coupler and/or horn
switch to ground are
faulty and must be
repaired.
EAS00798
2. The tail/brake light fails to come on.
1. Tail/brake light LEDs
• Check the tail/brake light LEDs.
• Are the tail/brake light LEDs OK?
8 - 38
ELEC
1
Br
P
2
NO
circuit The horn is OK.
YES
Replace
brake light assembly.
– +
YES
NO
the tail/