A couple days ago all of my passenger side speakers stopped working; the three on the door and the one next to the rear seats. All other electronics on the passenger side seem to work fine (windows, mirror adjustment, etc). Any idea what could have caused this or what could solve it?

 

Amp could be bad but check audio settings that balance isn't set all to left

 

My passenger side small door speaker wasn't working, so I took the panel off to find one of the two wires that connect directly into the speaker was no longer attached... can I just glue it back to the connection point on the back of the speaker??