I don't know that specific rig but I have tinkered with a few class B's and van conversions.
My best guess would be under the hood on the passenger side or underneath the van on the passenger side just behind the passenger door.
2004.5 Dodge 3500 5.9 Cummins, NV5400, 5" turbo back stainless exhaust, Edger programmer & 22.5 Alcoa's
2002 Forest River 36 5th Wheel (staying home)
1992 Jayco 29 5th Wheel (Mexico veteran & headed back)
2002 "faux" Wanderlodge 40' My new toy....