Upgraded to Sony Head Unit and Sound Got Worse + Sub Issues

Hello everyone, I own a 2007 Limited V8 4runner that I love. One of the first things that I have done to it, is I upgraded the HU (head unit) with the Sony AX 4000 and it was installed by a Geek Squad from the Best Buy. Ever since then, the quality of sound was very dull while subwoofer can't be adjusted and barely makes any sound. Specifically I can't adjust the volume of the sub nor can I turn it off/on - it functions like a speaker with a very poor quality.

After some research I hope to get some feedback about my thought process:
- "Non amplified audio" output used on the PAC RP4-TY interface while the harness that is used to connect car and HU connectors used for the "typical 2004-2013 Amplified." (I circled used connectors from the PAC instructions).

My question is - is this correct? I am at a loss. Anything obvious that I am missing?



More info:
The issue with poor quality of sound started right after installation of the new HU.
JBL logo is present on the speaker on the dashboard and on the old HU.
Car has the sub on the back, but I do not have JBL logos on the plastic covers.
When switched to the "Amplified Audio Output" on the PAC, the sound becomes more quite and still bad.

 

Welcome. Without digging into your wiring,it sounds like the amp is not powered on. You'll still hear sound through a non powered amp but like it's a stadium that's 20 miles away with a Taylor swift concert.

Since you paid for the install, i would say take it back and have them busy out multimeters on the wiring instead of trying to dig in it yourself.

Only my opinion though.

 

Exactly, sound of the sub is very muffled and can only be heard if you get very close to it. I will be taking it to them in a month (first available appointment), but it would be helpful to know what could be causing this issue when guiding the conversation. Thank you for helping brainstorm this, I am just dying to know what had caused it...