1981 GMC c1500 Truck wont start?

I have a 1981 GMC c1500 L6 and my stereo wouldnt save the settings, so I looked under the dash and to the fuse box was a wire connected from the stereo to my fuse box and i pulled the wire and plugged the stereo in to the hot wire to remember the settings and now my truck wont start, i have all other electrical, just wont start.