Yamaha YFZ450S 2003 Service Manual page 364

EBS01086
4. Radiator fan motor
• Disconnect the radiator fan motor coupler
from the wire harness.
• Connect the battery (DC 12 V) as shown.
Positive battery lead → blue 1
Negative battery lead → black 2
• Does the radiator fan motor turn?
YES
5. Circuit breaker (fan motor)
• Remove the circuit breaker from the wire
harness.
• Connect the pocket tester (Ω × 1) to the
circuit breaker.
Circuit breaker resistance
Zero Ω at 20 °C (68 °F)
YES
NO
The radiator fan
motor is faulty and
must be replaced.
NO
Replace the circuit
breaker.
COOLING SYSTEM
EBS01088
6. Thermo switch 1
• Remove the thermo switch 1 from the radi-
ator.
• Connect the pocket tester (Ω × 1) to the
thermo switch 1 1 as shown.
• Immerse the thermo switch 1 in a con-
tainer filled with coolant 2.
• Place a thermometer 3 in the coolant.
• Slowly heat the coolant, then let it cool
down to the specified temperature.
• Check the thermo switch 1 for continuity at
the temperatures indicated below.
Coolant temperature Continu-
Test step
Less than 98 ± 3°C
1
More than 98 ± 3 °C
2
More than 92 ± 3 °C
3*
Less than 92 ± 3 °C.
4*
Steps 1 & 2: Heating phase
Steps 3* & 4*: Cooling phase
8 - 41
ELEC
Thermo switch
(208.4 ± 5.4 °F)
(208.4 ± 5.4 °F)
(197.6 ± 5.4 °F)
(197.6 ± 5.4 °F)
– +
ity
NO
YES
YES
NO