My Vulcan Powerhouse high efficiency electronic gas management system ?

My above unit has a white control box with DSI Indicator, Summer Fan and Economy buttons below the heating control box on my wall. These used to light up when pressed but now dont, and I have never been given any instructions on how to use it, so dont know if I have inadvertently turned it off or not? I would like to use the Summer Fan, but have no idea how or even if it works.
Can anybody help me...?
Thank you so much