Need Help with a Motor Guide

I have a Motor Guide W75 saltwater series wireless. I had to replace the mother board and now I need to reset the foot control. I rehooked everything up, hit the + and - at the same time and it beeps. The only problem is the control does not respond after that. I was advised that the memory in the foot controller might be full from info storred from the last mother board. Im stuck and rather frustraited. The trolling motor came with the boat when I got it and need the mother board from the get go. Any help is greatly appreciated

If I remember right you have to disconnect the + battery terminal, then while holding the + and - buttons connect the cable. It almost takes 2 people.