What was found
CABIN DOOR ANNUNCIATOR ILLUMINATED IN FLIGHT. PRIOR TO ENGINE START, ALL 9 FLAGS WERE VISIBLE, ALL 6 PACK LIGHTS EXTINGUISHED, & CABIN DOOR ANNUNCIATOR EXTINGUISHED. AFTER TAKEOFF, CABIN DOOR ANNUNCIATOR ILLUMINATED CLIMBING THRU APPROX 2,000 FT. AFT LOWER 6 PACK LIGHT NOT ILLUM WITH DOOR OPEN. CLOSING MCD EXTINGUISHES ALL OTHER LIGHTS, BUT CABIN DOOR MASTER CAUTION STAYS ON. ACCESSED LOWER AFT MCD SWITCH & FOUND PLUNGER ON SWITCH STUCK. SOLDERED WIRES TO NEW SWITCH IAW STANDARD PRACTICES MANUAL 20-30-30 INSTALLED NEW LOWER AFT MCD SWITCH & AFT INTERIOR DOOR TRIM PIECES. MCD ANNUNCIATOR, 6 PACKS LIGHTS, EMERGENCY LIGHTS INCLUDING NEW SWITCH FUNCTIONS NORMALLY. REF SPM 20-30-30 & MM 25-20-05 FOR MX PERFORMED.