Hi,
Your husband is thinking clearly, wanting the wiring and piping diagrams. Good for him and you.
Going into this cautiously is key to doing less work later. However, in this case, those types of drawings do not exist.
I can pass this along, as I have had many Sunlines apart, although the ones I have had apart are newer ones. Sunline still uses similar building methods to your older one.
Normally, fresh water piping and wiring do not run in the floor joists' cavities.
Fresh-water piping (PEX or P
is run on top of the floor, inside the living space, and not under the floor or in a wall cavity. You can see this starting at the water pump, with the water lines lying in the back of the cabinets on top of the floor. There can be a city water pressure fitting on the side wall of the camper to the outside, and a pump suction line from a freshwater tank under the camper if the freshwater tank is under the camper. Many campers have the fresh tank inside the living space and not under the camper. So the odds are very low that fresh water piping is in the floor joist cavities.
LP gas piping, you can see the main LP gas line under the camper, a 1/2" NPT black iron pipe (not most likely rusty) that runs from the trailer tongue hitch area LP tanks down under the camper, and then tee's off to copper flexible tubing to go up through the floor and hook up to a gas appliance in the living space. You can see each branch tubing hookup under the camper and then under the cabinet where the appliance is located.
Drain piping for the sinks, shower, or toilet passes straight down through the floor from inside the camper and connects to drain piping or a grey or black water holding tank under the camper floor system. Again, no long pipes are buried in the floor joist cavities; those drain pipes can be seen inside from a sink, etc., and then go straight down through the floor, and some are run under the camper, exposed, so you can see them to the dump valve area.
Next is the wiring; there are three types of wires, and some of them pass straight up or down through the floor, as the drain pipes do.
DOT wiring. There is a 7-wire truck plug at the ball coupler area that powers the DOT lights (clearance, marker, tail, and stop lights) on the camper and the trailer's electric brakes. This is all 12-volt DC. These wires are buried in the wall cavities and can pass straight down through the floor. Under the camper, these wires can be exposed. You can trace them from the 7-wire plug and the battery cables to where the wires will go up through the floor into the living space or into a wall cavity, but they normally do not run along the floor in the joist cavities.
Internal 12-volt DC wires: these wires start in the power converter area, run up inside the wall stud cavities, up into the attic, and back down a wall cavity to come out where 12-volt DC power is needed to run a water pump, fridge, lights, fan, furnace, and radio. Again, normally not in the floor joists.
120 VAC power wires to run the power converter, a roof AC unit if you have one, an electric heating element in the fridge if yours has that option, a microwave, again, if yours has that option, and normal home-looking 120 VAC wall outlets. There is an incoming 120 VAC shower line cord/vinyl-covered cable that passes through a wall and connects to the power converter area and a circuit breaker box. The 120 VAC uses Romex solid wire, which runs through the walls and ceiling cavities to get to where it needs to go. Again, normally not in the floor joists.
Under the camper, there is a moisture barrier; the older campers used a metal membrane under the floor to keep road splash water and dampness from getting into the floor joist areas. The sheet metal was replaced with a thick black plastic wrap called Darco as the years went on. Be careful not cut into the bottom membrane, or you will have to repair it when you take out the floor.
So, "normally," there are not long runs of wires or pipes inside the floor joist cavities. I say normally, and 99% of the time, that we do not have to run wire or pipes for joist cavities. But there is a 1% chance that a 120 VAC shore-line power wire "might" be buried in a floor joist. This is unique in that the floor plate forces it to happen, as the camp power post is normally on the left side of the camper, while the power converter inside the camper is on the right. The 2004 T317SR had this setup (I have one of these). The floor plan forced it, so never say never. Go into the floor system cautiously, and you will be OK.
I hope this helps.
John
