i bought a 94 accord ex and the cd player and cigar wont work, the guy i bought it from said that when he would hit a bump it quit working and then hit another bump and it started again and the hit another and it quit again, is it the ground and how would i find the bad ground and where it is grounded to

 

get behind the dash and look at the wiring. take detailed pics and i can see if there are any glaring issues.

i ground to the chassis floor.

if they replaced the HU and you see wire nuts, electrical tape, etc. then you have to re-do the install/wiring properly.