High Temperature Shutdown Switch - Toro Groundsmaster 3505-D Service Manual

High Temperature Shutdown Switch

The high temperature shutdown switch is located on the
water pump housing on the rear of the engine block (Fig.
20). The shutdown switch has a blue/white wire con-
nected to it.
The Standard Control Module monitors the operation of
the high temperature shutdown switch. If the ignition
switch is in the ON position (engine running) and the
high temperature shutdown switch closes due to exces-
sive coolant temperature, the Module Over Tempera-
ture Shutdown input LED should illuminate and the
engine should shut down.
Testing
CAUTION
Make sure engine is cool before removing the
temperature switch.
1. Make sure ignition switch is in the OFF position. Low-
er coolant level in the engine and remove the tempera-
ture switch.
2. Put switch in a container of oil with a thermometer
and slowly heat the oil (Fig. 21).
CAUTION
Handle the hot oil with extreme care to prevent
personal injury or fire.
3. Check continuity of the switch with a multimeter
(ohms setting). The high temperature shutdown switch
is normally open and should close between 225 to
o o
235 F (107 to 113 C).
4. Allow oil to cool while observing temperature. The
high temperature shutdown switch should open at about
o o
219 F (104 C).
5. Replace switch if specifications are not met.
Groundsmaster 3505--D
6. Install switch to the engine housing.
A. Clean threads of housing and switch thoroughly.
Apply thread sealant to the threads of the switch.
B. Thread switch into the housing. Torque switch
from 16 to 20 ft--lb (21.7 to 27.1 N--m).
C. Reconnect wire to switch.
7. Fill engine cooling system (see Traction Unit Opera-
tor's Manual).
1. Water pump housing
Page 5 - - 17
2
1
Figure 22
2. Shutdown switch
Figure 23
Electrical System