3 Birds need to duck because..

So, I'll go out on a limb and assume the A/C system is new to you, and that you do have two A/C units on the roof. You do have to select the Zone 2 by simultaneously pressing the top two buttons on the thermostat. This brings up the information for the bedroom A/C. You can then set the mode (Fan, Cool, Heat Pump, Furnace,or Off)and the temperature desired. The bedroom unit will operate then according to what you have set. If bedroom unit is not on you will still feel some air coming from the bedroom ceiling registers but this is only what can be supplied by the front (Zone 1) unit. Hope this helps.