Amber, Have battery and alternator checked to be sure they are functioning properly. Make sure all grounds under the hood, in the cabin , battery connections and the ground buss are clean/corrosion free and tight.
Ground Buss corrosion is sort of a known issue that can make the symptoms your vehicle is demonstrating.
The ground bus connection is at the bottom of the a pillar where wires run under carpet or front door kick panel/ rocker/sill area, I believe there is a ground buss on both driver and passenger sides of the car to check and clean/repair.
Will post links to show ground buss. Check the attached links,instruction and guides. Good luck
I hope this helped you out, if so let me know by pressing the helpful button.
http://www.pontiacbonnevilleclub.com/forum/1992/topic2008.html
https://www.google.ca/search?q=pontiac+bonneville+ground+bus+connection&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjm3eOuvtvPAhUK0IMKHR-xCX8QsAQILg&biw=1024&bih=681#imgrc=_