In a similar posting, I touched upon the fact that there are different types of grapes found in this world..............there are ornamentals, such as Crimson Glory Vine (Vitis coignetiae) which are intended to climb and have beautiful colors, and there are fruit producers, known as common grapes (Vitis vinifera) which flower and produce grapes when conditions are favorable.
Here is the link to that above mentioned discussion:
If your particular vine is an ornamental, you will most-likely never see a cluster of grapes for as long as you or the vine shall live!
However, if your particular vine is supposed to be a producer, you could have potential environmental problems, mineral deficiencies, inadequate sunlight, water, and the list goes on and on.
If you are convinced that your vine is a producer, let the forum know, and perhaps someone can aid you in alleviating the problem.
T. Shane Freeman