Identify a leak by finding a visual stain on the roof or wall, smelling mustiness from damp cloth, feeling high humidity inside the trailer or by finding a crack in the roof, wall or window. External leaks are generally easy to identify but search the edges of all windows and seams where panels may overlap on the outside walls or roof for any visible proof.
Caulk the edges of the windows on the outside if the window. Apply a small layer of clear exterior silicone caulk with a caulking gun, run a gloved finger down the edge to push the caulk into the seam thoroughly and wait for the caulk to set. Replace the window if it is visibly cracked. Caulk the window on the inside if the window still leaks after the exterior caulk has fully set.
Re-coat the roof with a roofing tar or gel sealant if the roof is leaking. The appropriate roof sealant depends on whether the RV roof is metal or not. Paint sealant on the seams and edges with a brush. Support your body weight by placing wooden planks across the top of the trailer roof.
Plug your trailer into a generator or electrical source with an extension chord.
Flip on and off all of the switches for your lights, water pump and other appliances.
Replace the light bulbs or lights themselves if they do not work.
Bring the trailer into an RV repair shop or auto body shop if your new lights or appliances are not working, as the problem is in the internal wiring. Do not attempt to replace or repair electrical wiring unless you are an electrician as you can permanently ruin the electrical setup of the trailer.
Run a hose into your holding tank and water systems separately to observe if there are any leaks.
Replace leaking hoses and tanks and tighten bolts on hose clamps before running water through again. If these repairs do not fix the leaks the problem is in the pipes.
Clear any blockages in your plastic or metal pipes using a drain cleaner. If the trailer has been sitting for a while it is possible that insects or dust could be clogging the pipes.
Tighten all plumbing joints before running the hose through again. If the system still leaks you will need to replace the pipes and joints to ensure solid fittings. Consult a plumber if you find no remedy for the leak.
Connect your propane tank to your trailer by screwing on the connecting hose to the tank.
Turn the power knob on your propane heater knob to "Pilot" and light the pilot light with a match.
Turn off the heater if it does not produce heat. If you smell garlic, the propane is running but the heater is not lighting. If you smell and feel nothing you may need to replace the hoses. Test your propane oven and stove similarly by turning them on and lighting the heaters with a match. Turn them off if they are unproductive and notice if you do or do not smell the garlicky propane smell. If you smell the propane then it is running through the tubing and the problem is in the regulator or the lighting element of the appliance.
Clear out the tubing of the heater by removing the tubes via the external heater access and cleaning them in water. Dry them thoroughly. Reconnect them and ensure the tube clamps are secure before attempting to fire up the heater again.
Test to see if the problem is in the wiring if the heater or stove and oven still do not function. If it is particularly cold outside, heat up the regulator by the propane tanks using a small hand warmer or other small warming device. The propane appliances may not work at all if the regulator is frozen. Contact an electrician if you believe the problem to be in the wiring.
Hitch your trailer up to a truck with a high enough towing capacity to pull it and drive slowly.
Press the brake pedal and feel if the trailer responds to the electrical brakes or whether it keeps moving.
Take the trailer to a mechanic and get the brakes fixed if the trailer did not respond to your brake pedal, as this is one area that should be left to an expert.
