Oh, Oh, Sprung a LEAK

[MarcusN]

Was de-winterizing 5er yesterday for the 1st time and slowly working through everything and all was going good. Then when had wife open the taps one by one going good in bathroom and then onto kitchen sink. Heard air clearing line and then I (on the outside) heard water spraying (leaking) underneath. Had DW turn off taps and as I looked in through the access panel for the water filter could see water running down in behind. I figured it must be a leak in the drain pipe as DW said nothing shows under sink. Called dealer (7PM still open) and he thought it was probably a connection failed. Don't know how sitting over the winter (dealer winterized) would cause that to happen and everything was fine when winterized and there wouldn't have been any water in the drain past the trap anyway.
So there is good news and bad news. Good news is it happened 2 days before 1 year warranty expired but the bad news is he can't get to it until after Memorial day holiday and so we are losing 2 weekend of camping, at least.