Insects love warm electrical components and air conditioners are full of them. If you want to keep insects out, experts say do not use insecticides, because the electrical components will not like them. One option is to get a special cover for your relay switch, but be aware that it has to be installed by an air conditioning technician. The cheapest (and easiest) way to keep them away is to use a flea collar. To install the flea collar, shut the power off to the air conditioner and simply placed the collar near the relay switch.
To stop airflow between walls and floors, Install foam gaskets on all outlets and switches, and use child safety plugs backed with punch-outs to keep the cold air from coming through the sockets. Remember, be careful whenever working around electricity.