MFI
BLK
Temperature Sensor
(Closed When Hot)
BLK
TAN
7
3
Electrical Systems
7.48
Coolant Temperature Warning Circuit Op eration -- Carbureted Models
The MFI light is controlled by a temperature/warning switch installed into the engine cooling system. When engine
coolant temperature sensor reaches its “ON” temperature (see page 7.1) the switch closes, completing the cur-
rent flow from the wire harness through the MFD and to ground. The system should be tested periodically for
proper operation.
Temp erature Warning Circuit Test
W arning light in MFD is activated when temperature switch contacts are closed (overheat condition) and ground
path is complete. On Polaris engines, the sensor is located on the exhaust manifold. Ground the sensor wire
from MFD with engine running to see if temp light activates. Refer to MFD function/testing in this section.
Temp erature Sensor Test
The temperature/warning switch is normally open. Using a digital VOM set in the Ohms position, and with the
wires disconnected, contact one test probe to the switch terminal and the other test probe to engine ground. The
meter should show an open circuit. Heat the switch in a water bath to the “on” temperature listed on page 7.3.
Measure resistance of the switch. Reading should be less than .4 ohms.
CAUTION:
When testing the switch, heat only in a water bath. Never subject the sensor to an open flame or sensor damage
will result. Do not immerse the wires in the water bath.
Coolant Temperature Sensor Wiring Diagram -- Carbureted Models
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