Vehicle: 2006 Manual with Navi

Bought the car recently without working audio (FM/CD/tape all don't produce any audio). The audio randomly works once every now and then for a minute or so, and then the audio stops again. So far, I've tried swapping amps with another TL, checked every single fuse in the car, and even taken out the headunit and reinstalled it to make sure everything was plugged in, etc.

Any ideas on what could be causing this? Do I need to simply get a completely new head-unit?

 

Update:

Took the radio off another TL and put it in mine to test it. The audio works! Hope this helps someone in the future who has the same problem.