Temperature Sender (Workman Hdx And Hdx--D); Thermal Fan Switch - Toro Workman HDX Service Manual

Temperature Sender (Workman HDX and HDX- -D)
The temperature sender is threaded into the water pump
housing on the engine (Fig. 30). The resistance of the
temperature sender reduces as the engine coolant tem-
perature increases. This resistance change is used by
the instrument cluster to display engine operating tem-
perature. There is a yellow wire attached to the sender.
Testing
1. Park machine on a level surface, raise bed, stop en-
gine, apply parking brake and remove key from ignition
switch.
2. Install bed support on bed lift cylinder to prevent bed
from lowering.
CAUTION
Make sure engine is cool before removing the
temperature switch.
3. Lower the coolant level in the engine, remove wire
harness connector from temperature sender and re-
move the sender from the engine.
4. Put switch in a container of oil with a thermometer
and slowly heat the oil (Fig. 31).
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 resis-
tance of the meter and test leads. Subtract this value
from from the measured value of the component you are
testing.
5. Check resistance of the sender with a multimeter
(ohms setting) as the temperature increases. Replace
sender if specifications are not met.
COOLANT TEMP TEMP SENDER RESISTANCE
o o
100 F (38 C)
o o
160 F (71 C)
o o
200 F (93 C)
o o
220 F (105 C)
6. Replace temperature sender if necessary.
Electrical System
460 ohms (approximate)
140 ohms (approximate)
54 to 78 ohms
50 ohms (approximate)
7. Install switch to the water pump.
A. Clean threads of water pump housing and switch
thoroughly. Apply thread sealant to the threads of the
switch.
B. Install switch into the water pump housing and
tighten. Torque from 16 to 20 ft- -lb (22 to 27 N- -m).
C. Connect yellow wire harness wire to switch.
8. Fill engine cooling system.
9. Remove bed support from lift cylinder and lower bed.
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1. Water pump housing
2. Temp sender
Page 8 - - 22
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Figure 30

3. Thermal fan switch

Figure 31
Workman HD Series
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