Could be wiring of the actual car. I would first make my own solid ground. Then run your own main line to the battery and tap in the acc wire from under the dash.
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Alarm: Viper 5200
HU: Stock
Active Set-Up
Tweets: Image Dyamics CD1pro mini horns
Mids: Sundown Neo Pro 8s
Amp: Kicker IX500.4 (2)
Sub Stage
Subs: (2) Dayton Audio 15" HF
Amp: Kicker IX1000.1