A/C malfunctioning

My AC system started acting up end of last year. What happens is I get only hot air blowing while in AC mode and it's really hot.

I have tried using recycled and outside air setting but that doesn't make a difference.

Today however it kicked in and blew ice cold. So it would appear that it's not a coolant or compressor problem.

Any one have thoughts or similar experience.

Thanks much for any ideas