Polaris 2005 Sportsman MV7, Service Manual

Page: 271 / 312

ELECTRICAL
10.15
SPEEDOMETER
TROUBLESHOOTING CONT’D
TEST 7 -- -- RESET SPEEDOMETER
If the key switch or engine stop switch is turned off with
the vehicle in motion, the speedometer indicator
needle may stick, indicating the speed at which the
vehicle was traveling when the speedometer lost
power. For example: If the ATV was traveling 30 mph
when the engine stop switch is turned off, speedo may
indicate 30 mph until reset:
1. Operate vehicle at a speed greater than indicated
on speedometer (past point where needle is stuck).
Needle should return to normal operation.
2. In the above example, the ATV speed would have
to exceed 30 mph to reset.
COOLANT TEMPERATURE
SENSOR (THERMISTOR)
TEST
Thermistor
If the thermistor circuit is open the engine Hot light and
fan will both come on. With engine cold, disconnect
lead and measure resistance of sensor between the
two Yellow/Black connector terminals. There should
be no continuity or very high resistance (see chart
below).
See “Engine Temperature Controller” on Page 10.5
for information on thermistor operation.
SITUATION OHMS
READING
DIAGNOSIS /
ACTION
Hot light ON &
Fan ON
Above 50k Open Thermistor /
Replace Thermis-
tor
Hot light ON Below 178 Engine Overheat
or Bad Thermistor
THERMISTOR READING DURING OPERATION
Condition Approx. Reading
(Min--Max)
Temperature
Hot Light
On
178
Ω
-- 190
Ω
215
°
F
(102
°
C)
Fan Off 296
Ω
-- 316
Ω
180
°
F (82
°
C)
Fan On 236
Ω
-- 251
Ω
195
°
F (91
°
C)
Room
Temp
1940
Ω
-- 2060
Ω
77
°
F (25
°
C)
COOLING SYSTEM HOT
WARNING
OPERATION/TESTING
The Blue/White wire out of the Sure Power box is
connected to the speedometer head. In normal
operating conditions, the wire is non-conductive
(open). If engine coolant reaches the specified
temperature, this wire becomes conductive,
completing the path that causes the word ’HOT’ to
display in the LCD panel.
With engine cold, disconnect the harness and
measure resistance of the thermistor between the
connector terminals and ground. There should be no
continuity.
Hot Light On Approx. 230
°
F (110
°
C)
THERMISTOR BYPASS TEST
1. Disconnect the thermistor harness.
2. With the ATV in “Park” and with the parking brake
on, turn the ignition key (and engine stop switch)
“ON”. The fan should start running.
3. If the fan does not run or runs slowly with the
thermistor harness pulled, check the fan motor
wiring, ground, and motor condition (refer to Fan
Motor Testing this section). Also, testing with a
known good Sure Power box can aid in identifying
if that component is the problem.