Radio not working

The radio is the original factory radio..basic am/fm no cassette, cd or anything aftermarket. We have unplugged, replugged. Unhooked the antenna and then re hooked it. He took out the radio, and replaced it with one just like it, both work well when not in the truck.. My son went looking for answers but only found out something about a part that is supposed to go from the antenna to ???? Supposedly the antenna gets hooked into it and not the radio? I'm sorry I can't be more clear or to the point, but I don't know many technical terms. I've tried to insert a picture of the radio land how it looks when the truck is turned on.

I will try to find the 2nd radio he has tomorrow.I wasn't able to find it in the garage.
I also couldn't get the wiring diagram to open up to where I could read it.
I apologize for taking up so much of your time on this but it is appreciated and will help my sanity if I can somehow get it fixed. I'm having my son come over on Friday to try and work on it.
I will donate more to you on Friday for all your hard work as I get paid then.
If I can find the radio, I will also send you a picture of it, maybe that will be more helpful!

My email address is "onegrandpaal@yahoo. Com

Ok so I need a diagram for a 1992 gmc Sierra 1500 radio. I have the original radio that came with it but there are a set of yellow and white wires hanging out of the bottom of the dashboard. I took the dashboard part to see what it was to and it's to the radio just like I thought. Now I'm trying to find a diagram showing where the wires go and I'm not having any luck with it so I need a diagram for the radio

I have those three plugs but there is a yellow and white wire that needs to b plugged in but I don't know where they go

All wires are hooked up the yellow and white wires are connected to the radio

They are hooked up to the back of the radio