2008 Yamaha Raptor 250SE / 250SE2 Factory Service Manual, Page 301Get this manual
SIGNAL SYSTEM EBS01083
3The carburetor heater fails to come on1Thermo switch Disconnect the thermo switch from the wireharness Connect the pocket tester (!1) to the thermo switch leadTester positive probeblack Tester negative probeblack
2Carburetor warmer Remove the carburetor heating element from the carburetor Connect the pocket tester (!1) to the carburetor heating elementTester positive probeheating element Tester negative probe "# heating element body