What was found
(CAN) WHILE IN CRUISE FLT "ESSENTIAL BUS" WARNING LIGHT ILLUMINATED ON CAWS PANEL. NR 2 BATTERY OBSERVED TO BE DISCHARGING AT APPROX 35 AMPS & SELECTED TO OFF POSITION. DISCHARGE RATE FROM BATTERY STOPPED & "ESSENTIAL BUS" LIGHT WENT OUT. WITHIN 3 MINS AOA CAUTION LIGHT CAME ON & LT WINDSCREEN FROSTING OVER. EMERGENCY LANDING REQUIRED & CARRIED OUT WITHOUT INCIDENT. MAINT PERFORMED GROUND RUN & FOUND FOLLOWING: NR 2 GENERATOR INDICATING 28.5 VOLTS BUT NO AMPRE OUTPUT. WHEN PROBE HEAT & LT WINDSCREEN HEATING WERE SELECTED ON. NR 2 BATTERY WOULD SHOW DISCHARGE OF 35 AMPS. THE NR 2 GEN RELAY REMOVED & BENCH TESTED. MAINT FOUND THAT TOP SET OF CONTACTS IN RELAY WERE NOT CLOSING.