Left signal light stay on solid

One of your bulbs on the left side is probably bad, may even be the rear one or a side marker, any light that is related to turn signals. Look at right side first with turn signal on to see what should be lit, then check the left side.

See the guides below, they will help you figure this out

https://www.2carpros.com/articles/turn-signals-not-working-blinker

https://www.2carpros.com/articles/turn-signal-bulb-replacement

https://www.2carpros.com/articles/turn-signals-blink-rapidly

Hello.

My mom has a 1995 Oldsmobile Ciera. The right turn signal works but not the left. I changed both bulbs on the left but they are not blinking only the right? How do I fix this?

I checked the front bulb turn signal and it's working. So no issue there.