Yamaha 2004 YP400 Service Manual page 376

EAS00791
4. The auxiliary lights fail to come on.
1. Auxiliary light bulb and socket
• Check the auxiliary light bulb and socket
for continuity.
Refer to "CHECKING THE BULBS AND
BULB SOCKETS"
• Are the auxiliary light bulb and socket OK?
YES
2. Voltage
• Connect the pocket tester (DC 20 V) to the
front turn signal light assembly coupler
(wire harness side) as shown.
È Front turn signal light assembly (left)
É Front turn signal light assembly (right)
Positive tester probe → blue 1
Negative tester probe → black 2
È
L
B Ch
B Ch L
2 1
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) of blue 1
on the front turn signal light assembly cou-
pler (wire harness side).
• Is the voltage within specification?
YES
This circuit is OK.
NO
Replace the auxiliary
light bulb, socket or
both.
É
L
B Dg
B Dg L
2 1
NO
The wiring circuit
from the main switch
to the front turn sig-
nal light assembly
coupler is faulty and
must be repaired.
LIGHTING SYSTEM
EAS00792
5. The license plate light fails to come on.
1. License plate light bulb and socket
• Check the license plate light bulb and
socket for continuity.
Refer to "CHECKING THE BULBS AND
BULB SOCKETS"
• Are the license plate light bulb and socket
OK?
2. Voltage
• Connect the pocket tester (DC 20 V) to the
taillight assembly coupler (wire harness
side) as shown.
Positive tester probe → brown 1
Negative tester probe → black 2
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) of brown
1 on the taillight assembly coupler (wire
harness side).
• Is the voltage within specification?
This circuit is OK.
8 - 32
ELEC
YES
Replace the license
plate light
socket or both.
Ch Dg Dg
B L/R Br
1
YES
The wiring
from the main switch
to the taillight assem-
bly coupler is faulty
and must
repaired.
– +
NO
bulb,
Ch
B
2
NO
circuit
be