Hello all and thanks for your time in advance.

I recently installed a new JBL basspro 12 powered box in my 2017 rdb pro (with nav, no JBL). I use the high level speaker inputs on the box/amp to splice a wire into each of the front speakers, behind the headunit.

The box powers on, door speakers all work fine but I get barely any noise out of the sub.

Regardless of gain settings, headunit settings. I rechecked all connections. Ground seems fine. Swapped the speaker connections just to check.
Everything seems fine yet I at a lost. The sound is barley noticeable inside the cabin, and the woofer does not "hit" or move at all.

Also, the woofer makes a loud pop sound when I turn the car on and off. Louder than it plays any song...

Has anyone experienced something similar? If so, how did you resolve it?