Grandpa is a good symbol, which can lead you in the correct decision in a particular situation. The main thing is to figure out what he wants to say to you through the dream.
The meaning of any night vision depends on whether the grandfather was alive or not, and also on whether it is your grandfather or a stranger.
If you dreamed of own grandfather, who is alive and healthy, this dream indicates that it is better to visit him as fast as possible, because he thinks about you and misses you.
There are various interpretations of the dream if a grandfather is dead. First of all, dead relatives are seen in a dream when the weather is changing dramatically and unexpectedly. Secondly, it may be that you often think about him or have not visited or cleaned his grave for a long time. Furthermore, most likely your relative wants to tell something to you and suggest what to do next.
Of course, we should not hide the fact that such a dream sometimes indicates a danger which threatens anyone of your relatives alive.
If you see a grandfather happy and cheerful, it signifies that you're doing everything right, and soon you will be successful.
Moreover, it is a very wise sign emphasizing that you have enough wisdom to find the necessary and reliable solution in a given situation.
Modern dream books note that if a woman sees a dream with her grandfather, it means that soon she will meet a real man, with whom she will build strong and lasting relationship.
But if the young lady sees a dream in which her strict grandfather is going to visit her, she should be careful with own actions, words and decisions. Chances are that an act which she will make soon will negatively impact her reputation, position in society and relationship with loved one.
A stranger grandpa is telling you to change own behavior and not to perform bad actions.
Perhaps you lack of wisdom, in order to assess present condition of a situation and make the right decision. If so, it is better to seek advice from someone you trust and who certainly knows how to act in a particular situation.