Factory Stereo Amp Location needed?

Just wondering if factory amp took a crap on me because I have no sound coming from speakers anymore? Does anyone know where the location is? Harness is good also head unit is good. Just no sound anymore. When I did have sound it would cut out only when it rained or high humidity. unplugged door speaker that was blown and no sound out of any speakers now. Replaced rear speakers with crunch audio speakers awhile back ago. Also have mice in my car but cant find any chewed up wires.