I have the following :

Sony MEX-M100BT
Soundstream pn4.1000d amp
Scosche handlebar control interface
2012 FLHTK

I don't use my radio every time I ride but I just noticed that the rear speakers have a very low volume. I checked the gain, switched the rca cables, and confirmed that all the speakers work. What should I check next? Either my head unit or amp took a crap. The amp is working and the green light is on and the front channel works. The head unit is less than a year old and never got wet. I'm not great with audio and wiring it, but I'm 99% sure everything worked not too long ago.

 

Check your crossover switch on the rear channel and make sure it didn't get bumped to LPF.

 

I already messed with them. I could have messed up some wiring with the headunit. The amp is pretty straight forward. What else do I need to check?

 

Is it possible some settings got changed in the hu like fade. Not familiar with that model so not sure of options

 

I reset the head unit and it works now. I must have changed something on accident.