Just bought a 2009 335QBQ. This model has a shower, sink, and toilet in front, sink in the galley, and a sink and toilet in the rear bathroom. I was told I have two black tanks and two grey tanks (grey and galley). There are two valves mid way under the camper and two at the side of camper on the 4" black lines. I have one grey valve on the front drain, but no grey valve on the back drain. Three questions:
1. What are the two valves on the 4" black lines midway under the camper for?
2. Are the grey tanks (grey and galley) somehow connected?
3. I see Black, Grey, Galley, Fresh, and Battery indicator lights on the panel inside. Why is there only one black tank indicator light?
I attached a sketch of what I see under the camper to help clarify my rambling above.
Thank you in advance for any assistance.