Trudy,
You didn't say what particular feature of the Sani-Con stopped working but I suspect it's the Macerator rather than the valves. Have your Hub go back by the Sani-Con & valve switches and put his hand behind the pump switch. He'll probably find 2 female push-on (Sta-Kon type) connections.
As they are exposed and prone to corrosion, simply pulling them off the terminals and pushing them back on can often help.
As a side, when this happens to me I'll most often replace the switch with a waterproof type having sealed wires coming out and solder the leads into the system I'm having problems with. I'll then shrink-wrap (put the shrink-wrap on the lead before you solder) the soldered area and, after shrinking the tube, finally apply liquid tape. On simple 2 position on/off (SPST or DPST) switches there are no polarity concerns. I've done this so many times over the years I've amassed quite a collection of used switches I'll someday find a use for (yeah - right! - anybody interested in a used but good 1968 collector's edition MOPAR rocker switch?).
Aimee,
If you want to try, send me one of the schematics. I'll use Auto-Cad to make a pictorial diagram that many may find easier to follow. But, do it before the weather changes and we hit the road again (the Windows 7 machine I carry while traveling doesn't like Auto-Cad).