What would cause both the brake light and the abs light to stay on, for a 1998 dodge ram 2500 pickup? Could the brake switch be defective? Fluid o.K. And no leak in lines. Could one of the sensors be defective?
The ABS light is telling you there is a problem that can prevent the system from working properly. That can include the three things that make the red brake light turn on.
First check the brake fluid level. If it is real low, there is a leak. If it is just a little lower than "minimum", the front brake pads are probably worn to the point of needing replacement. Don't fill the fluid to the top, just enough to make the light go out.
Be sure the parking brake pedal is fully released.