Power Problems 2000 denali

I keep loosing power to my radio windows and windshield wipers it goes in and out. I was told it might be the BCM, thoughts!

Thoughts???????

You may want to check the ground wire coming from the battery to the frame rail. It may have rusted at the frame rail and has loosened or the rust is keeping it from making a good connection. Also, check the battery terminals for corrossion and give them a good cleaning.