Toro 3000D manual Temperature Sending Unit GM 3000-D, Electrical System 6 22 Rev. a

Temperature Sending Unit (GM 3000–D)

The temperature sending unit is located on the top right side of the water outlet box, which is located on the front end of the engine block. It has a blue connector with gray and violet wires. The violet wire supplies a signal to the high coolant temperature relay from the switch compo­ nent of the sending unit. The gray wire supplies a signal to the temperature gauge from the thermistor compo­ nent of the sending unit (Fig. 36).

CAUTION

Make sure engine is cool and coolant system is depressurized before removing the temperature sending unit.

1.Lower the coolant level in the engine and remove the temperature sending unit from the engine.

2.Put the switch in a container of oil with a thermome- ter and slowly heat the oil (Fig. 38).

CAUTION

Handle the hot oil with extreme care to prevent personal injury or fire.

3.Check continuity of the switch component with a multimeter (ohms setting). Check continuity between post 2 and the sender casing. The switch is normally open and should close between 226 to 234_F (108 to 112_C) (Fig. 37).

4.Allow the oil to cool. The switch should open below

226_F (108_C).

5.After oil has cooled below 158_F (70_C), slowly heat oil and switch again (Fig. 38).

6.Check resistance of the thermistor component with a multimeter. Check resistance between post 1 and the sender casing (Fig. 37).

A.The resistance should be about 390 ohms at

158_F (70_C).

B.As the temperature increases,the resistance should be about 143 ohms at 212_F (100_C).

SENDING UNIT

Figure 36

TO TEMP GAUGE (VIOLET WIRE)

TO HIGH TEMP RELAY (GRAY WIRE)

Figure 37

Figure 38

Electrical System Page 6 – 22 Rev. A Groundsmaster 3000/3000–D