The hold light on a 1990 Mazda Protege indicates that the transmission is in "Hold" mode. In this mode, the transmission will automatically shift between first and second gear, depending on the vehicle's speed and engine RPM. This mode is typically used for driving in hilly or mountainous terrain, or when towing a trailer.
To turn off Hold mode, simply press the "Hold" button on the dashboard. The light will turn off, and the transmission will return to normal shifting mode.
