What was found
PDIS 103 05-50 8035 24FEB21 PEN FACT U LOGPAGES:3216466 BURNT RUBBER SMELL IN COCKPIT PASSING 7.5K TO 11K THE SMELL REOCCURED AGAIN PASSING 210 THRU 230 NOTICED THE SMELL OF RUBBER ON PREVIOUS LEG HOLDING SHORT OF THE RWY 20R CAN THOUGHT IT WAS FROM LDG A/C BUT THE SMELL WAS THE EXACT SAME ON DEPRARTING OUT OF BKK FACT 24FEB21 03:32 PEN U UPON FURTHER TROUBLESHOOTING, FOUND BURNT SMELL COMING FROM LEFT LIGHTING PANEL ON OVERHEAD P5 PANEL. REFER WRI 33-40/8038 FOR MAINTENANCE ACTION. AIRCRAFT OK FOR SERVICE. MDIS 103 33-40 8038 24FEB21 PEN FACT  REFER WRI 05-50/8035, DURING TROUBLESHOOTING FOUND L RUNWAY TURNOFF SWITCH (S1) BACK PLASTIC CASING MELTED DUE TO METAL SHAVING SHORTING THE TERMINAL TO THE BODY OF THE PANEL. FACT 25FEB21 04:36 CAN REMOVED AND REPLACED THE LEFT TURNOFF LIGHT SWITCH PER CMM33-11-71 AND PERFORMED RUNWAY TURNOFF LIGHT OPS TEST PER AMM33-42-00-5 NORMAL.DMI CLEARED AND STICKER REMOVED.A/C OK FOR SERVICE.