My S2000 I bought from someone came with an aftermarket headunit, appears to be wired with a streetwires power station amp kit. A while ago, the radio audio would intermittently cut on/off. Then one day, there was no audio at at. I just replaced the headunit, so I think that's ruled out as the problem. I checked the radio fuse, it seems to look ok. The streetwires fuse by the battery looks ok as well. Anyone have suggestions on what's causing the issue? Unfortunately I know very little about how audio is wired, was trying to avoid a costly trip to a shop if it's something I can fix at home.

 

You mention an amp wiring kit, but you don't mention whether there is an external amp installed.
If there is, could be loose wiring to the amp or a failing amp.
If there isn't, if the power to the headunit stays on, but the sound stops, the problem likely
lies somewhere between the headunit and the speakers. A loose wire would likely cause only one
speaker to cut out, but a wire shorting out might cause the headunit (or external amp) to go into
protection mode cutting off all sound.