So was it the amp wiring that was ripped out (I take it the amp is attached to the box)?
Is there a phase switch on the amp that may have been bumped?
To check if it may be wiring (maybe chaffing on the interior light wires to the boot or something) open the boot and then use a large board or heavy blanket across the opening. If it is being caused by sound waves (box positioning or speaker phase) the bass will die the same as having the boot closed, if it doesn't then the boot wiring is the problem.