There could be a number of reasons why the air conditioning system is not functioning properly, and it will be necessary to diagnose the issue to determine the cause.
Here are a few things you can try:
Check the fuse for the air conditioning system. The fuse for the air conditioning system is typically located in the main fuse box under the hood. Check the fuse to see if it is blown and replace it if necessary.
Check the compressor. The compressor is responsible for pumping refrigerant through the air conditioning system. If the compressor is not functioning properly, it could prevent the air conditioning system from turning on.
Check the refrigerant level. If the refrigerant level is low, it could prevent the air conditioning system from turning on.
Check the air conditioning controls. Make sure that the air conditioning controls are functioning properly and that there are no problems with the buttons or switches.