Yamaha YXR70FX Service Manual page 470

EBS01081
5. The differential gear lock indicator light and/
or four-wheel-drive motor indicator light fails
to come on.
1. Four-wheel-drive motor switch (differential
gear motor)
• Check the four-wheel-drive motor switch
for continuity.
Refer to "CHECKING THE SWITCHES".
• Is the four-wheel-drive motor switch OK?
YES
2. Wiring
• Check the wiring circuit from the four-
wheel-drive motor switch to ECU and ECU
to meter assembly (yellow/blue).
• Is the wiring circuit properly connect and
without defects?
YES
SIGNALING SYSTEM
NO
Replace the differen-
tial gear motor.
NO
Properly connect or
repair the wiring cir-
cuit.
9 - 40
3. Voltage
• Connect the pocket tester (DC 20 V) to the
meter assembly coupler as shown.
Positive tester probe → brown/yellow 1
Negative tester probe → black/white 2
Y/L Br/Y B/W
O/B R/W
O/B R/W
Y/L Br/Y B/W
1 2
• Set the main switch to "ON".
• Measure the voltage (12 V) of brown/yel-
low 1 and black/white 2 at the meter
assembly coupler.
• Is the voltage within specification?
YES
Replace the meter
assembly or ECU.
– +
ELEC
NO
The wiring circuit
from the main switch
to the meter assem-
bly coupler is faulty
and must be
repaired.