2010 Equinox LT 2.4L

Cluster is not functioning.

A few things:

1. I heard what sounded like electrical shorting in lower left dash and then the next time I started it, no cluster.

2. The check engine light does show briefly in the cluster at start up, but other than that it is completely blank. No gauges, nothing.

3. I have tried changing the fuse(s), did not work.

4. I bought a second hand cluster online and replaced it, still did not work.

So my questions are -

What could it be?

Where is the ground for the cluster?