Sorry I can’t help with your problem. Not long ago I was bs’ing with some friends, both have been GM techs since the 1980;s. I recall them both agreeing, GM cars from the 90’s had the most problems with electronics. The dinosaur age of automotive electronics, most of it was very low quality with a high failure rate. You might be wise to just unload the car and get something newer.
Overall quality was poor in that decade, the 1990’s.
