Jesse burkhamer

So my 2018 GMC sierra 1500 parking brake has disconnected from the ratcheting wheel that locks it. Not sure how to put it back but it looks like this.....

I have a 2018 gmc sierra slt and I have a 15" Kicker L7 hooked up. I am using the blue and grey suwoofer wires coming from the bose amp but that signal only plays 30hz and higher and is tuned for higher bass. I need an un filtered signal so I can use my amp to play the selected frequency and not the bose amps crossover settings.

Trying to find the unfiltered signal going into the bose amp in my 2018 sierra slt. Everything I see online tells me to tap into wires that are filtered by the amps crossover which does not give me the low frequencys I'm trying to achieve. Can someone help?