There would not be a separate pump for fresh water wash down, it would use the galley/head fresh water pump. To my knowlege there are only one or two TC 255's with more than one water tanks (I had requested a second tank--and the factory would not install it--said that they had only done than on an early boat because of the delays the owners had sustained. I do have the tank, and will have to take the furniture out and cut the floor to put the second tank in this winter.
Another very important function of the raw water pump is to wash mud off of the anchor and anchor chain/line.
The intake is on the inner side of the port hull, and there will be a strainer over the intake thru hull.
For fresh water rinses, we installed a fresh water hot and cold shower--this hose will reach most of the cockpit area, if we need to rinse off any salt etc. incidently you will get plenty of salt in the boat from spray, unless you have a full camper back.
The boat should come with complete documentation of systems. I have most of the manuals for the systems, but like most boats, there is no "boat manual" as you might find in a car--because the electronics and many other parts of the systems are different in each boat. We have a binder plus a multi section file which we keep onboard for the various manuals and instruction sheets.
If your boat was on the lift, I would suspect that you were not getting water because the thru hull was clear of the surface. You don't want to use any stagnet water for washing, for it will sour in the system. Use only clean sea or lake water for the washdown--or if you have to use the system in a poluted area, rinse it well with clean water as soon as possiable.