Checking The Radiator Fan Motor; Checking The Coolant Temperature Sensor - Yamaha WR250F Owner's Service Manual

• Positive tester probe 
Black "1"
• Negative tester probe 
Black "2"
b. Measure the resistance of the resister.
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CHECKING THE RADIATOR FAN MOTOR

EAS2GB2400
1. Check:
• Radiator fan motor
Faulty/rough movement  Replace.
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a. Disconnect the radiator fan motor coupler
from the wire harness.
b. Connect the battery (DC 12 V) as shown.
• Positive battery terminal 
Blue "1"
• Negative battery terminal 
Black "2"
1
L
c. Measure the radiator fan motor movement.
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CHECKING THE COOLANT TEMPERATURE
EAS2GB2401
SENSOR
1. Remove:
• Coolant temperature sensor
EWA
WARNING
• Handle the coolant temperature sensor
with special care.
• Never subject the coolant temperature
sensor to strong shocks. If the coolant
temperature sensor is dropped, replace it.
1
2
2
B
12V
ELECTRICAL COMPONENTS
2. Check:
• Coolant temperature sensor resistance
Out of specification  Replace.
Coolant temperature sensor re-
sistance
2.51–2.78 k at 20 °C (2.51–2.78
k at 68 °F)
210–221  at 100 °C (210–221 
at 212 °F)
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a. Connect the pocket tester (  1k/100) to
the coolant temperature sensor.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Green/White "1"
• Negative tester probe 
Black/Blue "2"
b. Immerse the coolant temperature sensor in
a container filled with coolant.
TIP
Make sure the coolant temperature sensor ter-
minals do not get wet.
c. Place a thermometer in the coolant.
d. Slowly heat the coolant, and then let it cool
to the specified temperature indicated in the
table.
e. Check the coolant temperature sensor for
continuity at the temperatures indicated in
the table.
9-78
G/W B/L
G/W B/L
1 2