It will only ever work on days when it isn't hot.
Our second car is old. The air conditioning works very intermittently. Maybe for about five minutes for every hour of driving time.
That five minutes never coincides with times when it is really really hot, and you actually want the air conditioning to be working.
It seems to take great delight in coming on when it's not needed. Like when I'm driving at night. Or in a cool southerly breeze.
Unfortunately, the engine in this car is still going strong (as the rest of the car disintegrates around it...) so it will be a while before we'll be able to justify replacing the car.
In the meantime I'll continue the routine of shivering for the five minutes that it's working in the cold weather, and dripping with perspiration when it refuses to come on in the heat.