Okay so I recently installed a pioneer double din head unit and these problems started shortly after. I switched back to my factory setup to troubleshoot and see if the problems were still there (they are)

Here are the problems I am experiencing

SRS light ON.
Speedometer Not Working
Gas Gauge Fluctuating up and down
Loss of Power when accelerating (engine itself is running great)
When Heat is set to head it blows out defrost (AC and defrost still work fine)

Battery tested at 12.6V
Alternator at 14.2V

I am at my wits end can anyone give me an idea of what I am experiencing?