Suspend the switch [A] in a container of coolant so that the temperature-sensing projection and threaded portion are submerged.
Suspend an accurate thermometer [B] in the coolant.
Note. The switch and thermometer must not touch the container sides or bottom.
Place the container over a source of heat and gradually raise the temperature of the coolant while stirring the coolant gently.
Using the hand tester, measure the internal resistance of the switch across the terminals at the temperatures shown in the table.
★ If the hand tester does not show the specified values, replace the switch.
Fan switch resistance:
- Rising temperature:
- From OFF to ON at 96-100°C (205-212°F)
- Falling temperature:
- From ON to OFF at above 91°C (196°F)
- ON: Less than 0.5 Ω
- OFF: More than 1 MΩ