I searched again and basically came up with the same answers. The problem could be the shift wire, it could be a fuse (someone mentioned #29), or it could be a failed cluster.
If I were you I would use the search feature here to see if you can come up with anything. If unsuccessful Googling "98 E150 cluster issues" will give you a number of results that you can look into.
Just be sure to come back and post up diagnostics tried and results in case anyone else here runs across the same issue.