I posted this last week:
On a 1992, there are TWO lights;
1. "Check engine"
2. "Maintenance Required"
The check engine engine light is used to determine problems in the engine control system, and flashes a sequence to indicate codes.
The maintenance required light is designed to go on at 82,500 miles automatically, regardless of status of the engine control system. This light is supposed to be a reminder to change the O2 sensor. Note: it does NOT indicate the O2 sensor is necessarily 'bad' or 'failed', but merely that 82K miles have passed, and the O2 sensor is probably in need of changing.
The maintenance required light can ONLY be reset by using a Chryco proprietary "DRB Scanner". Given it's relatively unimportant function (to remind one to change the O2 sensor), removing the bulb is the easiest way to deal with this. (Provided, of course, that one is certain the O2 sensor is in good working order!!)
All of this is straight from the FSM. (I used to own a 1992!)