Abstract: A temperature probe for use with an air conditioning device of the type including a heat exchanger subject to possible freeze-up, such as an evaporator tube array. The probe includes a substantially rigid support member having an elongated portion with a temperature sensor mounted thereto, as within a recess therein, for insertion into the tube array. Electrical temperature signals from the sensor are transmitted, as by electrical leads, to a use location and device. The rigid support member of the probe includes a limiting portion extending transversely of the elongated portion for limiting insertion into the tube array and thereby positioning the sensor. A second temperature sensor may be located on the support member so as to be external of the tube array for developing the air temperature signal. Both sensors may be thermistors. The elongated portion of the support member is sized for close-fitting insertion between a pair of fins which normally extend transversely of the tube runs.