im assuming the wires are cut. U need to get a light tester so u can find your 2 power sources(1 power will b all the time and 1 will b when u turn the ignition on) then just pop ur speakers out to see what color wires they are, then u can just make a new ground behind the dash somewhere. Simple as that. Ive done it plenty of times, cause ppl wanna b cheap and not buy a harness($5-$10 dollars at wally world), so they end up cutting the factory plugs(Idiots!!).