Backward wired alternator possible damage?

[Codie]

Just curious what kind of damage could happen if you were to wire an alternator backwards on this vehicle. A friend of mine just recently discovered his alternator is wired backwards and his gauge cluster has never worked since he bought it. The miles don't move and the speedo doesn't work. Could this have been caused by the alternator? We switched it back today and it still didn't fix the problem. Would changing the cluster be a good idea? Would the miles remain the same or change to the new cluster?

 

[whi tri]

Did it just blow the fuse because it was tying to draw current through cluster?