Have an issue with my 2014 V6 Convertible Premium

I have the shaker system with factory amp under drivers kick panel. Both doors have 8" subs. No trunk sub.

Suddenly my driver's door sub has very little sound. I have changed the speaker, no fix. Changed the amp, no fix. Verified wiring. And now replaced the entire radio with an aftermarket.

The strange thing is it works perfectly when on radio. The issue is only on Bluetooth. That's with the old factory radio and my aftermarket.

So it's SOMETHING in the car that is connecting the Bluetooth source to that speaker.

Any suggestions?? I'm at a full dead end here.

 

Does it do it with ALL bluetooth shources or just with a particular one? If it only does it with one particular one, then it's that one device with an issue. If it does it with all Bluetooth devices that connect, it may be an audio setting in the stereo.

 

Does it with any device. And now I've completely replaced the factory radio with an aftermarket and it does the exact same thing! So it's something in the car electronics BESIDES the actual head unit.