2008 Weekend Warrior FS2500

[307Camplife]

Does anyone have the plumbing schematics for a 2008 Weekend Warrior FS2500? 
We cannot seem to get the black tank to empty. We also have a leak somewhere and need to trace lines to find it. We found our pump, but our previous camper was much newer and we have no idea how to winterize this one. Google is less than helpful. 

[opnspaces]

Can't help on any documentation. But what challenges are you running into?
When you say you can't get the black tank to empty; What do you mean? Are you not able to pull the handle to drain the tank? Are you pulling the handle and nothing happens? Are you pulling the handle and it sounds like the tank drains but the gauge still reads full?

Are you sure there is anything in the tank? If you flush the toilet can you look down into the tank to see if it's actually full?

[307Camplife]

It doesn’t look full when we look through the toilet. I pull the handle to drain and it drains, not nearly as much as what I thought was in there, and the gauge still reads that’s there’s some left in there. Not full, just not empty. I’m wondering if there’s a clog or just needs cleaned. I haven’t messed with that part much. 
we found the small leak, looks like previous owners took out a water filtration system and tried to direct connect some hoses and the fittings are leaking. I located our pump but have zero idea how to winterize this thing. Our last camper had an inlet right on the pump you’d connect to and it would fill the lines. 

[opnspaces]

I would bet that the tank is draining then. RV's have notoriously inaccurate gauges on the holding tanks. Mine will sometimes read 2/3 after I dump it. After use and at the next dump it might read empty, or 1/3 or 2/3.
If you know the tank capacity, you could try dumping and then fill it through the toilet with a 5 gallon bucket until it's full. If you calculate anywhere close to the stated capacity you can assume it's just poor gauges.

You could also take the easier route and fill the tank until you know it's full. Then find a dump station and using a 3" dump hose (not a macerator) and dump while you listen. If you hear it rushing out and then eventually slows to a trickle you can be fairly confident it's dumped.