problem.. please help

[lgzmax77]

so i have a kenwood excelon kdc-x993 and it is hooked up to a soundstream dtr1.3400d and a dc level 5 12. the other day i was driving around and if i would turn the head unit up it would shut off and restart itself. i had a guy look at it and he said that the ground in the wire harness was a bad connection and then it started working. so it would start cutting out again and it was like i fixed nothing. after that happened a couple times it shut off and didnt come back on. so what i figured was a problem with the wire harness. what i did was take an old pioneer headunit i had with a completely different size wire harness and wired it up just how i had the kenwood and still nothing. i dont know what to do as much things as i try my head unit will not come back on