Hi johno5, you don't mention if you are trying to scan over the network or if you are trying to scan with USB. Here is the documentation from scanning from USB, Solved: WorkCentre 3655 Scan Via USB Cable - Customer Support Forum (xerox.com). If you don't have a scan app on the UI, it may be hidden from view and have to be renabled in CentreWare Internet Services (CWIS). I don't rememer the exact path so you would have to poke around. It should be something similar to this, Enable or Disable (Show or Hide) Service Icons on the Touch Screen (xerox.com), article.
I have a workcenter 3655i and we can scan from it, there is not function button on the printer it self that allows for this, how do we add this function and do allow for scans from the computer its connected to.