Not all temperatures sensors are created equal and not all instruments and controllers use the same type of temperature sensors. So the first step in troubleshooting or replacing this type of sensor is to first recognize the type of temperature sensor being used.
The suction line of a refrigeration system is normally insulated with a flexible, closed-cell elastomeric material. Insulating the suction line is done to prevent condensate from developing and dripping off. It also limits the amount of heat added to the refrigerant as it travels back to the compressor.
A popular electrical component used on many control circuits is the step-down transformer. It is the power source for a separate lower-voltage circuit which typically controls the operation of a system.