Did you ever get this working? Running into the same issue here with all drawers on the main unit.
I've done an I/O check on the vertical conveyor sensor & door sensor - both passed.
i would check the clutches all of them you might have a few other sensors going bad in the ADU main unit there are like 6 clutches in them. check though out if they move when you move the belt most likely they are bad they are not suppose to binding at all.
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