If your fan is only blowing on the highest setting, then the blower motor resistor may have failed. Try a search on this site to find out what that is. This can be a fairly inexpensive repair, so hopefully that's all it is.
RepairPal Certified shops can diagnose and repair your 1993 Chevrolet Lumina. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
thanks for the help, it took me awhile to find the resister. Had to repair connecter due to corrossin but now its working