Service manual

Groundsmaster 3280−D/3320 Page 6 − 13 Electrical System
Temperature Sender
The temperature sender is attached to the water pump
housing on the engine. There is a yellow wire attached
to the temperature sender.
If the ignition switch is in the ON position and the temper-
ature sender has reduced resistance due to high coolant
temperature, the High Temperature Warning indicator
light on the console and the Over Temperature Warning
input LED on the Standard Control Module should be il-
luminated.
Testing
CAUTION
Make sure engine is cool before removing the
temperature sender from engine.
1. Lower the coolant level in the engine and remove the
temperature sender from the engine.
2. Put the end of the sender in a container of oil with a
thermometer and slowly heat the oil (Fig. 13).
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 engine housing.
A. Clean threads of housing and sender thoroughly.
Apply thread sealant to the threads of the sender.
B. Thread sender into the housing. Torque sender
from 16 to 20 ft−lb (21.7 to 27.1 N−m).
C. Reconnect wire to sender.
5. Fill engine cooling system (see Traction Unit Opera-
tor’s Manual).
1. Temperature sender (gasoline engine)
Figure 11
1
1. Temperature sender (diesel engine)
Figure 12
1
Figure 13
Electrical
System