Yamaha XF50W Service Manual page 314

3. Voltage
• Connect the pocket tester (DC 20 V) to the
ECU coupler (wire harness side) as shown.
Positive tester probe
Negative tester probe
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) of black/
green© on the ECU coupler (wire harness
side).
• Is the voltage within specification?
YES
V
This circuit is OK.
-> black/green ©
-> black/white (§)
©
NO
I
The wiring circuit from
the main switch to the
ECU coupler is faulty
and must be repaired.
Refer to "CIRCUIT DIA-
GRAM".
LIGHTING SYSTEM
EAS00790
3. The tail/brake light fails to come on.
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?
YES
V
2. Voltage
• Connect the pocket tester (DC 20 V) to the
tail/brake light coupler (wire harness side)
as shown.
Positive tester probe
Negative tester probe
• Set the main switch to "ON".
• Measure the voltage (DC 12 V) of blue
the tail/brake light coupler (tail/brake light
side).
• Is the voltage within specification?
YES
V
This circuit is OK.
8-32
ELEC
4
NO
Replace the tail/brake
light bulb, socket or both.
-> blue ©
-» black
©
©
4
NO
wiring circuit from the
main switch to the tail/
brake light coupler is
faulty and must be re-
paired.
Refer to "CIRCUIT DIA-
GRAM".
+i
on