GE Dishwasher GDP645SYN0FS won't start

[BSCT]

Hey ya'll!

My GE dishwasher had been acting up for a while. It would beep randomly, and randomly cycle through the functions, then the buttons stopped working. I replaced the UI board, which went smoothly. No beeping, and all of the buttons/functions work, but when I press START it beeps 3 times and won't start. I held the Start and Cycle buttons for 5 seconds until all the lights flashed, they all stop flashing and stay lit when I closed the door. Any guidance on what my next steps might be? any help would be much appreciated. 

Thanks