Radio Fuse is Fine but radio doesn't work? 2003 F150
 

My Radio went out a few months back mysteriously which also causing the cigarette accessory power not to work, checked the fuse and it was fine. I checked all fuses and relays and they were fine. Then about 2-3 months later my wife got in the car, started it, and the radio started working again with no problems. A few weeks go by and then the radio went out again and has been out now for months. It is not the fuse and I am not sure exactly how to go about looking for where the short is. I had a short in my Overdrive wire (which I fixed) under the steering column which was blowing the fuse. I don't think it is related. Has anyone experienced where this short is coming from?