Mystery smoke from gauge cluster

I'm at a loss here. Why did you not disconnect the battery FIRST?
The battery was disconnected, I reconnected it to do a function test before installing the cluster, but I didn't realize the cluster was chassis grounded. I'm just worried that I'm going to reinstall the cluster and it's going to burn down before I can get it out. I have inspected the board throughly and I can't see any burned spots at all. Is it possible that the smoke was off the wire in the gas gauge?