Welcome to the forum its a great place to get your questions answered. It seems these drains are placed any number of places. Have you looked under your rig for two tubes extending out the bottom with caps on them? Hopefully someone with the same rig will pipe in here with what they have found.
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho