In my experience grapes should be pruned WAY back, now.
Don't hesitate to bring it into extreem control, even if you plan to have it grow next year. It will enjoy the severe cutback. You may want to lave sveral leaders that encompass the area involves, 2 or 3 may be appropriate, extending to the midway point of the trellace.

I just moved into my grandmothers house a year ago - she cared for 2 arbors but they both have been neglected for years. My husband pruned one waayyy back and it grew but no fruit. Should I prune again? Will I get fruit next year? We sprayed the concord arbor, no pruning whatsoever, and the grapes were plentiful but late in growing, turned black. Is this because of improper spraying? Should we do a cutback on this one? Should I just try to prune the dead to let more light thru?

I was wrong about when I used to prune grapes, it is spring!

here is some useful info

http://mtvernon.wsu.edu/frt_hort/grape_pruning_basics.htm

Lynette,
if you observe the proper pruning techniques, but still don't have fruit, then you most likely need more light.

If the vines have been in long neglect, most likely all the nearby trees and shrubs have been neglected too, or at least, have now grown tall enough that they are now blocking out light that the vines used to get.

I've found grapes need full sun, with no overhanging canopy stealing the light.