Yamaha YP400T, YP400V, YP400W Service Manual page 371

4. Voltage
• Connect the pocket tester (DC 20 V) to the
turn signal relay coupler (wire harness
side) as shown.
Positive tester probe → brown 1
Negative tester probe → ground
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) on brown
1 at the turn signal relay coupler (wire
harness side).
• Is the voltage within specification?
YES
Br/W
Br
1
NO
The wiring circuit
from the main switch
to the turn signal
relay coupler is faulty
and must be
repaired.
SIGNALING SYSTEM
5. Voltage
• Connect the pocket tester (DC 20 V) to the
turn signal relay coupler (wire harness
side) as shown.
Positive tester probe → brown/white 1
Negative tester probe → ground
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) on brown/
white 1 at the turn signal relay coupler
(wire harness side).
• Is the voltage within specification?
8 - 40
ELEC
Br/W
Br
1
YES
The turn signal relay
is faulty and must be
replaced.
– +
NO