I had a similar problem one time. The front of the MH would not go down when dumping. Mine has the HWH auto leveling system and there is a manifold at each end of the coach. The manifold has small holes for exhaust ports. Mud daubers like to fill those holes with mud!
I just used a drill bit (in my hand, NOT in a drill) to clean the dirt out. No more problems!
Good luck, happy trails, and God bless!
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Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD