Audio Systems: 1999 nissan altima car stereo, nissan altima, rear speakers

Question
i just put in a new sony stereo in my car and it worked fine until i pulled it out
to see if i might've missed a wire somewhere, bc the back speakers weren't
working...come to find out i did miss a wire and when i hooked everything back
up there was no power to the stereo...please help!

Answer
there is a ground wire missing on the harness look at the other end of the plug and you will notice that there is no ground you have to use the chasis metal
the rear speakers problem is that you need to turn on the rear amplifier using the blue wire of the new radio
good luck