Air conditioning

driving back from vacation in my father-in-law’s 4 or 5 year old impala, i noticed that the a.c. switch did not need to be on in order to make cold air. the recirculate switch did need to be on, however, along with the fan. my father in law was surprised to learn this, and did not believe it at first. obviously the compressor is running, but what then is the need for the a.c. switch? is this a max a.c. / a.c. mode thing? neither of us know how this is, and the manual does not address this. thanks!!

Do you have the defrost turned on? AC is active whenever the defrost is no in most cars.

It might help if you told us what year Impala you have.

It would be appreciated if you used capital letters where they should be and consider dividing your message into paragraphs as needed.

I am not a retired school teacher, but using these tools does make reading your message easier and you will have more people read it and replay. You will have a better chance of getting the answer you need.

On some cars, the compressor automatically comes on when the switch is on recirculate, or on defrost. The recirculate is, I believe, the same as max AC. In that position, most of the air from the vents is recirculated, and re-cooled, air from the passenger compartment.

Recirculate is useful for maximum cooling. Note it does not require more fuel. It gets air colder by re-cooling the same air instead of always cooling fresh, hot air.

The switch will activate the compressor when neither recirculation nor defrost is wanted. You may not want recirculation when you want to keep the insides of the windows dry, such as in rainy weather. You might also use the regular vent setting with the air conditioner when the recirculate setting produces air that’s uncomfortably cold (you could also set the temperature setting higher in this case).

The vent setting draws in mostly fresh air. You might use it with air conditioning if the air in the car becomes stale or too dry with the recirculate setting.

I use the vent and air conditioner (and heater, if needed) to keep the windows dry when condensation is a problem. I use recirculate for maximum cooling and vent with AC if that’s too cold. By experimenting you can find your own preferences for settings.