DURING MULTIPLE RWY OP GA SMA LINED UP WITH THE WRONG RWY. ADVISED THE ATCT LCL CTLR AND RECEIVED AN AMENDED CLRNC FOR THE OTHER RWY.

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ON APCH TO CLT; ADVISED EXPECT 23 FLY 320 DEGS/3000 FT. CHANGED TO EXPECT 18L TURN L TO 270 DEGS/2300 FT TO 2300 FT. SAW SMALL AMOUNT OF SMOKE COMING FROM UNDER INST PANEL IN AREA OF AUTOPLT AND INTERCOM. CUT OFF AUTOPLT AND INTERCOM. SHUT HEATER OFF. INST LIGHT DIMMED AND WERE TURNED OFF. GOT FLASHLIGHT ON. AFTER TAKING ABOVE ACTION MADE VISUAL CONTACT WITH ARPT AND LOCATED RWY LIGHTS. STARTED L TURN TO LINE UP WITH 18L; BUT SAW THAT I WAS LINING UP WITH 18R. INFORMED TWR I WAS ON 18R AND WAS IMMEDIATELY CLRED TO LAND 18R BY TWR. AT THE TIME OF 'CLRED TO LAND 18R' NO OTHER ACFT WERE IN CONFLICT AND NO EVASIVE ACTION WAS TAKEN. COULD HAVE MADE SIDE STEP TO 18L IF NECESSARY SINCE I WAS APPROX 3-4 NM FROM RWY. SINCE THE SMOKE/LIGHT FAILURE OCCURRED AT THE TIME OF HDG AND ALT CHANGE AND 'CLRED TO LAND' THE RWY WAS LOST AND THEN MISIDENTED ONCE THE SITUATION WAS CORRECTED. I DON'T THINK THE SITUATION COULD HAVE BEEN AVOIDED BECAUSE I HAD TO FLY AND TAKE CORRECTIVE ACTION. IT'S POSSIBLE THE TWR COULD HAVE SEEN ME FLY PAST THE CENTERLINE OF 18L AND ADVISED.