My dad has a 2000 Express work van, he parked it and the next day his FM reception was almost non existent. AM functions just fine, the radio can still find all the FM stations like normal.. But the volume is maybe 5% when turned to the max.

I bought a used radio off ebay from the same generation truck, plugged it in and same story.

Any suggestions? Thank you

 

Check the antenna

 

I did after swapping the radios, I wiggled the antenna wire around as much as I could along with a visual inspection and nothing.

 

The antenna might need replacing.

 

Check AM. A bad antenna would show up with absolutely no AM signals.

 

When you swapped the radio did you use and aftermarket one? Gm uses a smaller antenna plug, and you need an adapter to make it fit snug in the larger standard size used on all aftermarket ones...If its not tight, then it wont make a good connection.