I have had my subwoofers hooked up for quite some time now with no problems. Recently, and only SOMETIMES, when I shut my car off and open my driver side door, the subwoofers increase in volume steadily in a short time span then stop, increase in volume steadily in a short time span then stop, continuously until I shut my driver side door, then silence. If I open my door back up soon after shutting it, the problem continues to occur. When trying to show anyone this issue, it no longer occurs.. Imagine that. If I shut my car off and wait a while, nothing will sound, even when I open the door.
I have checked the the amps ground and it looks like the day I first installed it, no tears, no corrosion. I checked the length of visible positive wire from battery to amp, no tears, some corrosion on the battery terminal side on the ends of the wires, no corrosion inside the insulation of the wire. No corrosion amp terminal side. Any suggestions on what to do to diagnose the problem and/or fix it?