Ballingbob

I have a Bellaire 3000 Cal Spa that was built in 1997. I am having a problem where the display on top is not lighting up. I don't have any water in it now so I was wondering if there is any kind of pressure switch where it would cut the power to the unit unless there is water in the tub. Nothing will work so I took the control panel apart and I do have 240 volts to the panel underneath. Is it possible to get a schematic for the circuit board in the control panel underneath? Thanks for your help.