Hello eco1.2. From what you are describing it sounds as if your AC compressor is functioning, which is a good thing. It sounds to me as there is something else happening with the dampers or damper controls.
I wonder if the auto climate control is part of this? The lowest temperature that can be selected is 61, right? If outside air temperature is 50 degrees, maybe the auto climate control won't activate the AC at cooler outside temps.
The service manual has procedures to check various components. Some checks require special tools. Some checks can be done yourself without special tools. Do you have a copy of the service manual?
The automatic air conditioning controls have the AC compressor cycling as factory default. It's not a frequent point of failure, but a few forum members have reported a failed compressor. One of the first things I did when I got my Mirage in the driveway was to turn off the auto AC compressor operation.
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View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)