Welcome to the forum
The two line with the caps are the "low point" drains. They only empty the water out of the system and NOT the fresh tank. There should be another single hose hanging down or maybe a valve on the bottom of the fresh tank itself. You may need to figure out where the tank is located and then lay onderneath, It IS somewhere underneath,
As far as the slide goes, what type of slide is it?
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2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.