Check the Electrical System
Flip on your RV's main circuit breaker for the 120V AC system. Connect your rig to shore power and then test all the interior lights, appliances and air conditioner to make sure they're operating properly. Do not run the water pump at this time.
Turn on the TV, DVD and CD players, and fire up the satellite system. Install batteries in clocks, radios, detectors and alarms where needed.
See manufacturer's instructions for bringing your onboard or portable generator back to life, and be sure to unblock any exhaust pipe you sealed. Test all carbon monoxide, smoke and propane detectors for proper operation.
Note: Until you've reconnected your propane tanks, you won't be able to test the refrigerator in the gas mode or the furnace. Test these once the propane tanks are connected.
Inspect the Interior
Check the ceiling, walls, doors, vents and windows for any signs of discoloration or stains, as these could indicate possible leaks that occurred during the winter. Discard any baking soda boxes you opened to eliminate odors, as well as any moisture absorbent used to remove humidity. Run a vacuum cleaner over all flat surfaces to capture any dust, and also vacuum in and around all furnace ducts. Inspect the fire extinguisher to make sure it is properly charged.
Examine the Tires
Since your tires have spent the winter supporting thousands of pounds of weight, now's a good time to check the air pressure. Also, check for any sidewall cracks or worn treads in case replacements are needed, and be sure to remove any debris stuck in the treads.
RV tires don't get as much wear as standard truck or auto tires, but they still age. Any RV tires that are 5 to 7 years old should be replaced, even if they appear to be in good shape. You can tell when a tire was made by checking the DOT date code molded into the sidewall. The last four digits indicate the week and year of manufacture. For example: 3209 indicates the 32nd week of 2009. Finally, make sure the lug nuts are tightened to factory specifications.
Check the Exterior
Inspect the seals around exterior doors and windows and re-caulk where needed. This will help keep out gentle summer rains and the chill of autumn nights.
Scan the Roof
Make sure all roof vents are uncovered. Check that plumbing vents are unblocked and the air conditioner shroud is in good shape. Examine roof for any damage or leaks and repair.
Operate the Awning
Fully extend your awning and lubricate all pivot points or moving parts to ensure smooth operation all season long.
Look Over the Engine
For a motorhome, check oil, brake, transmission and power steering fluids. Also check the windshield washer reservoir and top off as needed. If you're mechanically inclined, check the hydraulic leveling system, rear axle gear oil level and the slideout reservoir.
Make sure the radiator is filled with automotive anti-freeze, and then inspect the engine compartment for any signs of animal nesting, cobwebs, or damage to wiring, belts or hoses. If everything appears okay, start the engine and let it idle; then check the brakes and brake lights, turn signals, headlights, backup lights and running lights.
Take your rig out for a test spin after you've completed all de-winterizing steps.