Dead fuel gauge; Dead eng temp; and dead OBC

[Shellback]

recently put all my interior back together from installing an aftermarket HU, RCA's and amp.
Everything worked fine but now I'm getting a strange electrical problem.

Car starts normally.
- After a few seconds after starting, the fuel gauge needle starts to slowly drop (move to the left).
- Then suddenly, the same needle and the temp needle all jump to the left (low range). In addition, the the fuel low light illuminates.
- Also, the OBC is dead. It has the -- lines as in waiting for me to set the correct time, but it will not allow me to set the time.
The OBC does not display any info (MPG, temp, etc.) after depressing the left OBC stalk on the turn signal lever.

Trying to retrace my steps right before the issue started:
- tucked in wires under the steering column (are there any wires there that would cause a problem?)
- finished up rear sub floor (had to manipulate battery cables a bit to make this happen).

Please let me know if you think of anything.
Thanks