ABS light stays on on a 1999 sat urn sl2

This is tough to diagnose without an abs scanner. But you can try. Look at all four wheels from under the vehicle. There are sensors on each wheel and if the wires break, short of get corroded this can cause the problem. Also if you get road dirt or grime or metal shavings from the brakes around the sensors it can cause issues.

ANY Dash Light you get, that comes on or stays on after
the motor is running is a possible problem & a possible
fault code should be checked for

I'm at a loss with this site & the questions, because we have had these codes & vehicle systems for well over 30 years, yet no one knows the vehicle is in trouble & you have to check for codes

You need to run to a repair shop within a day, every time any
dash light or check engine light comes on,not ask questions
or continue to use the car

Any codes you get can be googled, to find the system that set
the fault light