Service Manual

Groundsmaster 4300--DPage 5 -- 40Electrical System
High Temperature Shutdown Switch
The high temperature shutdown switch is located on the
water pump housing (Fig. 50). The high temperature
shutdown switch is normally open and closes when en-
gine coolant temperature reaches approximately 239
o
F
(115
o
C). When excessive coolant temperature causes
the shutdown switch to close, the engine shuts down.
There is a tan wire attached to the shutdown switch.
NOTE: If excessive coolant temperature causes en-
gine shutdown, the operator can restart theengine to al-
low the machine to be moved a short distance. After a
restart in this condition, the engine will run for approxi-
mately ten (10) seconds before the engine shuts down
again.
The TEC controller monitors the operation of the high
temperature shutdown switch. The s witch and its circuit
wiring should be tested as a controller input with the
Diagnostic Display (see Special Tools and Trouble-
shooting in this chapter).
If excessive coolant temperature caused the TEC con-
troller to shut down the engine, the Diagnostic light can
be used to identify the fault (see Diagnostic Light in the
Troubleshooting section of this chapter).
Testing
1. Park machine on a level surface, lower cutting
decks, stop engine, apply parking brake and remove
key from ignition switch. Open and supporthood togain
access to engine.
CAUTION
Make sure engine is cool before removing the
temperature switch from engine.
2. Lowerthe c oolant level in theengine and remove the
high temperature shutdown switch from the engine.
3. Put the end of the switch in a container of oil with a
thermometer and slowly heat the oil (Fig. 51).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or fire.
4. Check resistance of the switch with a multimeter
(ohms setting) as the oil temperature increases. The
hightemperature shutdownswitch isnormally openand
should close from 234
o
to 244
o
F(112
o
to 118
o
C).
5. Replace shutdown switch if specifications are not
met.
6. After testing is complete, install shutdown switch to
the engine housing.
A. Clean threads of housing and switch thoroughly.
Apply a light coating of thread sealant to the threads
of the switch.
B. Thread switch into the housing. Torque switch
from 22 to 28 ft--lb (30 to 39 N--m).
C. Reconnect harness wire to switch.
7. Fill engine cooling system (see Radiator Installation
intheServiceandRepairssectionofChapter3 -- Kubota
Diesel Engine).
8. Lower and secure hood.
1. High temperature shutdown switch
Figure 50
1
Figure 51