When you say flush do you mean run fresh water to clean them or are you talking about dumping the black tanks. if dumping maybe the one doing nothing may be plugged.
Sorry reread your post I see you are definitely flushing the black tanks. You would think they would have separate hookups for the hoses. Dealer should know.
__________________
2018 Ram 3500 6.4 Harvest Edition
2018 Cougar 27RESWE
|