How to test a fuel gauge?

[Magic1]

I just finished replacing the fuel sending unit in my 82 Sierra. The tank had a ground wire as well as the new sending unit so I grounded them both to the same point on the frame. I'm finishing up installing a new wire harness so the wire is all new. The cap that fits on top of the fuel sending terminal leading to the gauge was a little loose so I bent it just a little and it made for a tight fit and I've got the cluster plug wired up according to painless' instructions but the gauge still doesn't work. I'm using a used gauge cluster from a guy I bought it from and he told me when he pulled it out everything worked. Where should I start checking?

[Captkaos]

There is a post in the Tech section on this I am pretty sure.

[Magic1]

Ok. Sorry about that. Ill check