Inspect the structure, tires, interior and exterior of the fifth-wheel trailer to look for signs of damage or instability such as rust, wear, leaks or stains. Test out any parts that run or move to ensure they operate smoothly.
A fifth-wheel trailer doesn't have a motor to worry about, but the trailer has many other parts with the potential for damage, including the frame and plumbing system. Look underneath the camper to ensure the frame looks solid without rust. Walk around the outside and inside the trailer to look for warping, water damage or other structural problems. Check out the tires on the trailer.
Inspect the windows and siding, which can be expensive to repair. Windows should open freely. Siding should be smooth without any bubbling, peeling or separation.
If the fifth-wheel trailer has a pull-out section, slide it out to ensure it comes out properly. Check out any interior items that move, such as doors and drawers. If the table converts to a bed, go through the conversion process. All of these items should move freely.
Before agreeing to purchase a trailer, request to connect it to both water and electricity so you can check those systems. Run the water in the sinks, toilet and shower to look for any leaks. If possible, test out any appliances built into the camper to ensure you don't need to replace them.