2076 Can't move the boom/bucket while using left stick

[Mustang Gregg]

MY 2076 has developed a problem (after my brother in law used it). It moves forward, left, right, and aft fine. But when I'm in any motion, the bucket and boom control on won't operate until I let the motion stick back in the center position. Is there a dash switch that could be in the wrong position? I think I've tried every combination. The hydraulic oil level is full. Much obliged, Mustang Gregg