Speakers/subwoofer not working right (aftermarket head unit)

[jwahl16]

ok so i just came home from school the other day and my car has been sitting for about 3 weeks.

I have a valor its-700w head unit and dual speakers, sub and amp.

All of the speakers are quieter, i have to turn them up to 25 to listen instead of the usual 12-14. Also the back left speaker is not working, but when i switched the output cable with the back left, it started working and the back right stopped working. The back left was working at full volume two days ago and i watched it go out when i turned up the volume! Also if i unplug the subwoofer out cable and just touch it to the input cable the sub will hit randomly, so it still works. So i came to the conclusion that something is wrong with the head unit. Do you think thats accurate? I was actually looking to sell this car soon and now i have to deal with this! I guess it doesn't want to leave me

What can i do to test/fix the head unit?

 

[kt239]

Id first rule out incorrect wiring and loose connections on all components. After verifying the wiring is good then rule out the amp. If amp is working properly then that leaves the headunit. Check that all sub settings are what they should be and that the balance/fade are where they should be. Theres a weak link somewhere you just got to find it.