Vision: If you are talking to either one: you have made a wise decision, and a specific project is going to be successful.
If both your grandparents are deceased: expect to get help in a certain matter, or you have decided to live a more prudent life.
Depth Psychology: Grandparents represent the wisdom that is available to you.
If you use good judgment in the things you do, everything will turn out all right.
Wiser, more mature masculine or feminine parts of self.