[hharney]

The section below is from the SM. It's not real specific to the discharge light so I would check the bulb or the wire going to the bulb

5-52. OVER AND UNDER VOLTAGE WARNING CIRCUIT.
15-53. DESCRIPTION. The alternator system in- cludes an over and under voltage system. When
system voltage exceeds 31. 5 ± . 5V an over-voltage tripout sensor automatically disables both front and
rear alternators illuminating the red high voltage light. The amber discharge light and both alternator lights will illuminate as both alternators have been shut down and the aircraft storage battery is being discharged. To recycle the over-voltage tripout sensor turn off the "BATT" portion of the master switch. If the over-voltage tripout immediately re- curs, then turn off "ONE" of the "ALT" switch portions of the master switch and recycle the "BATT" portion of the master switch. Repeat this procedure using the other "ALT" switch to determine which alternator-regulator system is producing the over- voltage condition. The remaining alternator-regulator system may not sustain the electrical load. The am- ber "DIS" light will illuminate indicating a discharge of the aircraft storage battery. Turn off low priority electrical accessories until the amber "DIS" light is off. The amber alternator system light will remain illuminated.