Air condition don´t start, a honda civic

Air conditioning systems sometimes leak down and won't turn on when the refrigerant levels are too low.

Lift the hood and listen to the A/C compressor while someone inside the car turns it on.

Does the compressor engage for a second or two and then shut off?
If it does....you need to have your system checked for leaks and recharged.

If the compressor never comes on. Look at the A/C compressor relay. It should be under the hood in a little fuse box with other relays and fuses. When you find this relay you need to see if it works. You can buy a replacement relay and swap it or take it to a parts store and have it checked. Relays are 10-30 dollars and you should have three or four relays of the same type so a real cheap test is to swap a identical relay from an electric window or a defroster. You should see them sitting right next to the A/C relay if you have them.

Good luck and be careful!