Okay, I finally got to speak with a Jayco Tech and he pulled up the plumbing schematic. On my unit the grey tank #1 is located towards the middle of the tt. The valve is right beside the discharge connection. This tank is for the lavatory, shower and, kitchen sink. The grey tank #2 located towards the front of the unit is for a washer. The unit is pre-plumbed for a washer/dryer unit. Since I don't plan on installing one the second tank is serving no purpose and will not be used. I may modify the plumbing later on after the warranty runs out. The Tech did send me the schematic so that I could see this for myself.
2016 Jayflight 34RSBS
2008 Ram 2500 Mega Cab 4x4 / 6.7L Cummins