Stereo stopped working

When I looked into the fuse panel, I found that there is something connected to the radio fuse, pictured below:

Not sure what that is for, my only thought could be for the old school car phone that is wired into the car.

Idk if you have any aftermarket phone/radio wiring stuff going on in your car but on a unmodified setup, If the radio powers up,
then it's not a fuse, it's the radio itself.

I've collected quite a few of these and they all have different failure modes, some power up and only have AM,
some power up and have no sound, some don't power up at all. It's generally assumed to be the electrolytic capacitors that they
used inside the stereos drying up. This can also happen to the external amplifiers that some models used. It's not uncommon
in a lot of vintage electronics that generate their own heat.

Your best bet (if you want to keep the OEM radio) is to try and find a place local to you that can service old electronics.

That's assuming it's unrelated to any wiring job a PO might have done. You can always pull the radio out and jiggle some wires.

it's installed upside down Kidding

Alarm won't do anything to radio.

This is probably not it, but when I first got my 89 GLL with the steering wheel buttons, the volume was all the way down on the steering wheel and I thought the speakers were blown.

Did you try putting a cassette in?

I haven't tried putting a cassette tape in, too bad I didn't keep my collection! I may try tracking one down to see if that does anything. Other than that I am at a loss.