1992 Fleetwood Jamboree Searcher water system diagram?

I assume your asking how to protect the tanks during winter since your going to live in it full time in cold weather? They are located under the RV likely under the rear overhang - find the outlet pipe on the drivers side - it connects to two other pipes - the large diameter pipe connects to the black water tank and the smaller diameter pipe connects to the gray water tank.

Unless the rig came with the winterized package you will likely have to provide heat/insulation to these tanks if your going to be living in the rig during cold weather.

Edit. My 92 Jamboree came with an outside shower (rear passenger side cargo compartment) - it was source of constant leaks and would be tough to keep from freezing during the winter. I removed mine and capped off the line - something you should consider.

You maybe able to get drawings from Fleetwood. Locate the metal tag that shows the serial number, normally located next to the entrance door. Then go to Fleetwood RV web site and enter information.
This maybe of some help
Manual

Like Don said, you typically don't "winterize" your waste system. If not in use, you want to winterize your fresh water system by getting all of the water out and drawing some antifreeze into the lines. A small exception is you want to dump some antifreeze into your traps (sinks) so they don't freeze.

When water freezes, it expands. If its in a confined space like a pipe, that pipe will burst. But a little bit in a holding tank (black or gray) shouldn't hurt anything. I always dump a little antifreeze in the bowl, black tank, sinks and shower just for fun.

BUT, if you're living in it then you're presumably going to be using the water system. That introduces some complexities. You're going to want to keep the rig heated - at least at or a bit above freezing. If you have an external hose (city) water connection, you're going to have to keep that from freezing somehow. My RV is designed in such a way that all of the water pipes run through areas that get radiant heat from the furnaces so they don't freeze. Waste tanks are underneath and waste can freeze and prevent you from draining the tanks if you don't add some antifreeze. Again, this assumes you're using them.

As far as location goes, just follow the plumbing off of the dump pipe. It's usually connected to the black tank and a smaller pipe will feed into it from the gray tank.

You do not need to winterize the holding tanks. You usually only need to winterize the potable system IF, you have no heat, are not using the RV. Most people who live full time and are aruck in cold places will leave a faucet dripping over night.
You likely will not find any diagrams, so dont worry about one