I've tapped into interior fuses -
22 Sensing and Diagnostic Module Ignition
18 Instrument Panel Cluster Ignition
17 Auxiliary Power Rear
Black wire on your harness
Once I pull the key and open the door it'll pop after about 2/3 seconds, hard to tell if it's the subs or all my speakers, but it never has happened before so I "assume" it's the subwoofers popping. I've Googled a bit and have read some amps don't have a soft shut down and will pop no matter what, I'm using a Pioneer GM D-9601 partnered with Sound Ordnance B24 box/subs per Crutchfields compatibility check. No other interference (hissing/buzzing etc) just a small thump or pop once I open my door.
Best I've gathered is that the amp is still staying on to long somehow and I get a little backfeed, or I have a bad ground. I'm using an unpainted factory ground in the trunk area, so I'm certain enough it's not that. Trigger wire is 14 gauge and run from the passenger fuse box, under the steering column, up the pillar, behind the curtain airbags, down the rear driver side interior panel, and into my amp. RCAs are from your harness under the wheel, up the pillar with my trigger wire, pulled over into the headliner and run beside the sunroof (with the rear window washer fluid hose), run down the rear driver side panel again, and hooked to my amp. Power wire is along my lower trim panels on the driver side, bass control knob wire runs along my lower trim on passenger side. Sub wires are 8 gauge plugged in with banana plugs to the sub box.
If any of that helps, I'm comfortable that everything is run properly and spaced enough to avoid interference. But I went to a career school for carpentry and college for criminal justice, so I'm very likely missing something blatantly obvious. Interior is back together, only took a few pictures, tried to explain best I could.
If this link doesn't work let me know I'm not overly familiar with posting videos, not sure how well my phone picked up the sound either. On my phone I can't hear the bass any or the pop, on my desktop system that has a subwoofer I can hear it clearly.