Question regarding appropriate amp to push a Rockford P2D2

RonRizz

Its a dual 2 ohm sub, so you will only present 1 ohm to the amp, and the amp is capable of that load, so it is not your protect circuit. If I understand you correctly, you unplugged the RCA's from the amp, and it continued, so the issue is with your amp, for sure. Sounds to me like an inferior ground.
get your multimeter out, disconnect your sub at the amp, and check for power at the 12v+, and ground terminals. also check your remote + for power.
Then re-check at a different ground location. If all is well, switch it to ohms, and read your sub wires, make sure it is at 1 ohm, or 4 ohm, depending on how the shop wired it.
Southark did hit on something that could also be an issue, which is signal ground, but disconnecting the rcas from amp should take that out of the equation.
Its gotta be a bad ground.

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