Narrative:

Master caution light flickered during climb until 10000 ft. Unable to detect any annunciator lights. R1 door position light switch MEL'ed, overhead door 'forward service' light on constant. This led the flight crew to suspect the flickering master caution light as related to the bad R1 door switch and increasing cabin pressure stopped the master caution flicker above 10000 ft. Upon arrival in ZZZ1, captain again tested all lights and found #2 generator CSD lights -- low pressure and high oil temperature -- did not illuminate. The 2 light modules were pulled and there were no bulbs in either one. Flight crew relamped both lights and they tested normally. Crew noted previously cleared MEL 24-1A in logbook (#2 generator bus off-light was lamped). On climb out during flight back to ZZZ, we again got the flickering master caution, but were able this time, due to relamped CSD light to see a flickering CSD oil pressure light. When the CSD temperature switch was moved from in-temperature, which was normal, selected rise temperature, the rise temperature was pegged full hot. Checklist completed and #2 CSD disconnected. Called safety officer as we felt the missing light bulbs created a very serious safety situation. When ZZZ maintenance reapplied the MEL 24-1A, found out maintenance removes bulbs as part of MEL. They were not replaced when the MEL was cleared.

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Original NASA ASRS Text

Title: B737-400 MISINTERPS MASTER CAUTION LIGHT, WHICH IS FOR AN UNKNOWN CSD PROB WHEN THEY ASSOCIATE LIGHT WITH MEL'ED DOOR WARNING SYS AFTER TKOF.

Narrative: MASTER CAUTION LIGHT FLICKERED DURING CLB UNTIL 10000 FT. UNABLE TO DETECT ANY ANNUNCIATOR LIGHTS. R1 DOOR POS LIGHT SWITCH MEL'ED, OVERHEAD DOOR 'FORWARD SVC' LIGHT ON CONSTANT. THIS LED THE FLT CREW TO SUSPECT THE FLICKERING MASTER CAUTION LIGHT AS RELATED TO THE BAD R1 DOOR SWITCH AND INCREASING CABIN PRESSURE STOPPED THE MASTER CAUTION FLICKER ABOVE 10000 FT. UPON ARR IN ZZZ1, CAPT AGAIN TESTED ALL LIGHTS AND FOUND #2 GENERATOR CSD LIGHTS -- LOW PRESSURE AND HIGH OIL TEMP -- DID NOT ILLUMINATE. THE 2 LIGHT MODULES WERE PULLED AND THERE WERE NO BULBS IN EITHER ONE. FLT CREW RELAMPED BOTH LIGHTS AND THEY TESTED NORMALLY. CREW NOTED PREVIOUSLY CLRED MEL 24-1A IN LOGBOOK (#2 GENERATOR BUS OFF-LIGHT WAS LAMPED). ON CLBOUT DURING FLT BACK TO ZZZ, WE AGAIN GOT THE FLICKERING MASTER CAUTION, BUT WERE ABLE THIS TIME, DUE TO RELAMPED CSD LIGHT TO SEE A FLICKERING CSD OIL PRESSURE LIGHT. WHEN THE CSD TEMP SWITCH WAS MOVED FROM IN-TEMP, WHICH WAS NORMAL, SELECTED RISE TEMP, THE RISE TEMP WAS PEGGED FULL HOT. CHKLIST COMPLETED AND #2 CSD DISCONNECTED. CALLED SAFETY OFFICER AS WE FELT THE MISSING LIGHT BULBS CREATED A VERY SERIOUS SAFETY SIT. WHEN ZZZ MAINT REAPPLIED THE MEL 24-1A, FOUND OUT MAINT REMOVES BULBS AS PART OF MEL. THEY WERE NOT REPLACED WHEN THE MEL WAS CLRED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.