I’ve turned on both temperature sensor and display but the temperature isn’t displaying?

Mister Freeze sensor connection

Mr. Freeze’s Accufill® technology has optimized the distance between the A/C vent and the engine compartment for the most consistent signal.  Simply turn on your remote temperature sensor and clip on to center most vent then turn on your digital display at or near your low side service fitting by the engine compartment. NOTE: a minimum distance of 5 feet apart is required for the sensor and display to connect.