Rev. E
Groundsmaster 4100−DPage 5 − 24Electrical System
Temperature Sender
The temperature sender is located near the alternator
on the water flange attached to the engine cylinder head
(Fig. 36). There is a gray wire attached to the terminal
of the switch.
Testing
1. Lower coolant level in the engine and remove the
temperature sender from water flange.
2. Put switch in a container of oil with a thermometer
and slowly heat the oil (Fig. 37).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or fire.
NOTE: Prior to taking resistance readings with a digital
multimeter, short the meter test leads together. The me-
ter will display a small resistance value (usually 0.5
ohms or less). This resistance is due to the internal re-
sistance of the meter and test leads. Subtract this value
from from the measured value of the component you are
testing.
3. Check resistance of the sender with a multimeter
(ohms setting) as the temperature increases.
A. The meter should indicate more than 600 ohms at
70
o
F (21
o
C).
B. The meter should indicate approximately 460
ohms at 100
o
F (38
o
C).
C. The meter should indicate from 54 to 78 ohms at
200
o
F (93
o
C).
D. Replace sender if specifications are not met.
4. Install sender to the water flange.
A. Clean threads of water flange and sender thor-
oughly. Apply thread sealant to the threads of the
sender.
B. Screw sender into the water flange. Torque send-
er from 16 to 20 ft−lb (21.7 to 27.1 N−m).
C. Reconnect gray wire to sender. Apply skin−over
grease (Toro Part No. 505−165) to sender terminal.
5. Fill engine cooling system (see Operator’s Manual).
Figure 36
1. Temperature sender 2. Alternator
1
2
Figure 37
VOA
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