OK, you stated you swapped P connections on the Control board? Then it showed Zone 2 and Zone 2 functions? Did you have Zone 2 control board COMM cables connected at this time? Now, LOOK inside that P connection that did not work with a flashlight. Do you see any corrosion at all? You may have to remove the Galvinized cover on that box to get a complete look at the PC board. Check for corrosion on the board. There are 12 volt wire connections----BLACK and RED. Which Zone Board has the Black and Red connected to 12 volt power? The one in your pic(Zone 1)? The ONLY way Zone 2 would show up on the Tstat is if the DIP switches have Zone 2 turned on on the Zone 2 Board. The DIP switches are those white switches on that red block. IF you turn the DIP switch to Zone 2 on the Zone 1 board, then the tstat will show Zone 2. Zone 1 is the default Zone on the control boards and does not have a DIP switch. Last I asked for Year/Brand/Model RV. I need that. Doug