Stereo Wiring Ground Problem

My car stereo wont start, i checked all the speaker wires, nothing is touching metal. So, a friend of my dads suggested that the ground coming from the back of the stereo could be loose (he is very knowledgeable with cars). I have a 1993 Mercury Sable with the 3.0L v6, where can i find where that ground is hooked up to, it looks like it goes a way in, i cannot see it from the empty stereo spot, am i going to have to remove parts of the dash or is there somewhere i can find it by looking under the dash? Any help would be great, thx.

did u use a dmm to test your wires? also check your fuses.

Hmm, popped the stereo in again to see if it would work, and it worked again, i dunno, it doesnt make sense.

The ground wire should be black but you should know that. it will be connected to screw in the wall if you cant see it then taking the top part of the dash off to try to follow that. another way to see if it is connected easily is with a testing light. attach the clip to a hot lead then find an open spot on the ground like the plug block that goes into the headunit. if it lites up your good on the ground but other wise if that doesnt work reply back and maybe i can help some more.