My back speakers started cutting in and out then after a few days of that they both went out does this sound like an amp problem and if so can someone tell you where the amp is located on a 99 durango?

sound,s more like a speaker connection problem. than your amp. check your speaker connections first. to make sure they are plugged in all the way. and fit tight on the speaker. it they are . and it is still cutting out. you may need to trace the speaker wires. and see if they are getting pinched in the door jam. that is a usual culpret for speakers cutting out.