DeMcCrae wrote:
My 5th wheel is completely sealed underneath so I can't get to the lines. How about one of those tank heater type blankets to put on the undercarriage?
Everyone's fiver has a sealed underbelly. When you need to work under there you have to 'drop the belly'. A tasked dreaded by all. There should be many screws along the edge of the plastic, that's Coroplast by the way. You remove enough screws to pull down the coroplast in the area you need to work on. You will want a cordless screwdriver or a cordless drill to do this.
There will probably be a layer of fiberglass insulation being held up by the belly. Hopefully it will be -dry- fiberglass. If that is missing then you have an explanation why the pipes froze.
That's why I doubt a heater of any sort will work under the fiver since there is a layer of coroplast and fiberglass insulation in between the heater and the piping.