I'm having 2013 Ford Fiesta and I've noticed that when I set my AC to 23 C it doesn't blow cool air much, but when I lower the setting to 20/19 C then the cold air continually flows.
Six months ago I serviced a car and they told me it's my thermostat but I didn't have time to leave the car for change so I postponed to another service. On last week's service (in the different service center) I asked the guys to check AC again and see what needs to be changed and they told me this time it's my compressor failing and I need to replace it.
What I was able to read from internet, if AC compressor is failing I wouldn't be able to get cool air at any setting inside the car so I'm confused now as to what would be an actual problem. Could AC compressor work only partially and explanation from last week in the service center be plausible or would it really be just a thermostat problem?