1998 Buick Century windshield wipers just stop in-place

Electrical problem
1998 Buick Century 6 cyl Two Wheel Drive Automatic 87, 00 miles

hello and thank you. My windshield wipers work fine when they are on. They stop in the middle of my shield when I turn them off, after a complete rotation of wiping and sitting down. They recycle then stop right in my eye-view.
how should I proceed about fixing these? Updating my car is impossible. I am on disability. Again, thank you. Maureen