If you've improved the filter and opened all the registers and you are still not having airflow in the registers, deice the A-coil. Go the thermostat mode change from “Cooling” to “Off” and go the lover swap from “Car” to “On.” Let the blower run for at least 30 minutes http://heating-and-air-condition84947.link4blogs.com/19251739/not-known-facts-about-home-heating-repair