Yamaha YJ125S, Service Manual, Page: 274 / 294

7-36
- +
ELEC
EAS00798
2. The tail/brake light fails to come on.
1. Tail/brake light bulb and socket
8
Check the tail/brake light bulb and socket
for continuity.
Refer to “CHECKING THE BULBS AND
BULB SOCKETS”
8
Are the tail/brake light bulb and socket
OK?
YES NO
Replace the tail/brake
light bulb, socket or
both.
3. Voltage
8
Connect the pocket tester (DC 20 V) to
the tail/brake light coupler (wire harness
side) as shown.
Positive tester probe
J J J J J
green/ yellow
1 1 1 1 1
Negative tester probe
J J
J J
J
black
2 2
2 2
2
8
Set the main switch to “ON”.
8
Pull in the brake levers.
8
Measure the voltage (DC 12 V) of yel-
low green/yellow
1
on the tail/brake light
coupler (wire harness side).
8
Is the voltage within specification?
YES NO
2. Brake light switches
8
Check the brake light switches for conti-
nuity.
Refer to “CHECKING THE SWITCHES”.
8
Is the brake light switch OK?
YES NO
Replace the brake
light switch.
The wiring circuit from
the main switch to the
tail/brake light bulb
connector is faulty
and must be repaired.
Refer to “CIRCUIT
DIAGRAM”.
The wiring circuit
from the main switch
to the tail/brake light
coupler is faulty and
must be repaired.
Refer to “CIRCUIT
DIAGRAM”.
This circuit is OK.
SIGNALING SYSTEM
B
G/Y
1
2
Y L
L
B