If your air condition turn on and your thermostat is adjusted correctly, but your system is still doesn't cool, it could be due to a dirty or blocked air condenser. Make sure your filter is clean. If you have pets or used your air condition frequently, you may need to change your filter more often. Pull your filter out and see if you can see through it as a test. If your air conditioner is still not cooling air, you may have a problem with your compressor or refrigerant and will need to contact a professional.