My system is a Trane with a 1050xl thermostat and a companion thermostat. If you have one of those (or a related thermostat model), you can get into the service menu by going to "service" and holding down the tech access button for a period of time. There should be a damper check option in the menu which will allow you to trigger specific dampers and there are some other buttons that show you which dampers are hooked to what thermostat.