Speaker Problem.. Possibly Amp

[NaTe]

I recently installed a video interface, and being an idiot didn't remove the fuse. About a week later the left side speakers started crackling and not playing at full volume and now its at the point where i have to set the stereo to play only through the right side in fear of damaging the left side speakers. This problem is only apparent when playing XM Radio and CD, for FM and AM it works fine. My guess is I messed up the amp somehow. Any Ideas on what exactly happened and how I can fix it.

PS: I am over the miles for my warranty, and have done much of my own wiring in my leased vehicle and therefore would like to avoid taking it to the dealership.

Thank You