Kenwood KAC-9104D problem

[Indianabobo]

So i recently bought a kenwood kac-9104d, its an 1800 watt amp. puts out 900rms at 2Ohm and at 1ohm 900+ ive had another amp in there which was running just fine and ive got video to proove that, but i went to go hook this amp up and now sound/bass is coming out of it. ive checked my RCA's behind the HU and followed them to make sure they weren't cut or anything even hooked up another set of RCA. the amp comes on, isnt in protect mode, just doesnt play bass/music how would i manage to look on the mother board or amp what ever u want to call it to see if the rca cable plug in themselves are messed up, they dont look like it from the eye but could something be hidden that is causing this boiling up of my blood pressure since it is not working? I hope this is a simple fix