they all leak somewhere, sometime.
hiya mike,
OUTSIDE....
UNLESS you've been in a LOT of rain and have a mystery TOPSIDE leak, skip the pressure testing for now.
instead, get a ladder and go LOOK topside for dried/cracked/loose sealant around ANY opening.
check the tank vents, skylight, windows and so on...
on an 05 any sealant failures should be obvious, up there.
the BELTLINE trim right over the rear bumper can also let in standing water (several threads on that issue)
it's very easy to check the UNDER bed/garage hatch door gasket for fit and easy to snug up the turn latches.
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inside....
turn ON the shower with the wand placed on the floor of the shower pan and stay OUT of the shower, door closed...
IF water is coming from UNDER the shower pan in that condition, it could be the pan/drain, or mixer value or pipe fittings TO the mixer...
and ALL of the plumbing runs along the wheel well that is UNDER the shower seat...
so unfortunately IF that's where the leak it, the shower stall will need to come out (not likely but possible) ...
unless the pan drain is OBVIOUSLY the source or the pipes leading UP to the mixer valve (accessed under the sink)
often times shops will just start sealing things (plugging holes) till they find the right spot...
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water migrates, so it's hard to know if ALL of those wet spots are from ONE source moving around or multiple things.
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under the LAV (remove drawers, access panel and everything UNDER the sink) are MOST of the elbows, joints and back flow valves...
so that's a common place to find plumbing drips and a LOT is accessible there (if you are a monkey sized guy) ...
many of those pex fittings are HAND tightened and need a twist or 2 occasionally.
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if you are not the most handy fella, or new to RV'n it might be best to simply take the unit to a REAL a/s dealer and let them solve this .
the charge will be MOSTLY hourly labor rate but mystery water coming from somewhere INSIDE is not to be ignored.
and they aren't gonna be able to solve this via email, there are just too many possibilities...
cheers
2air'