I have a Chevrolet Aveo and the air conditioning blowing only hot air i don't know why

I had the same issue, and it turned out to be a heater core problem. There was a leak, causing the air to stay hot even when the AC was on. The solution was to completely disconnect the heater, and the cooling started working fine again.

This issue might be due to low refrigerant levels or a compressor problem, which prevents the refrigerant from circulating properly. Also, check the evaporator coil, as it might be clogged, causing the air to come out hot instead of cold.