dougrainer wrote:
Tiffin uses the PCS system Power EMS system. It sheds the compressor's if the amp draw is too high on some Tiffin models. You don't state what year Tiffin. That would help. On other Tiffins it sheds the complete Power to the AC's. Regardless, there is a EMS monitor panel in the RV usually located above the drivers seat in one of the overhead panels. On newer Tiffins with the LCD SPYDER control system this display is integrated in the 7 inch LCD panel in the Hallway by the middle bath. Doug
Problem solved! The SPYDER control system was set on 15 amps (don't know why) and changing to 30 amps works one AC and everything else that is necessary. Thanks to all for your help.
PS: This was a friend's new Phaeton and he went through the first night without air, but he is near the NE end of Florida and it was a cool night.