TRACK DEV ACR MLG LINED UP ON THE WRONG SIDE OF THE ARPT. MULTIPLE RWY OP PARALLEL RWYS.

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WHILE ON APCH TO DFW; RWY 18L SIDE-STEP TO RWY 18R; WE EXPERIENCED A FALSE GS AND LOC CAPTURE. WHILE ON THE INITIAL VECTOR AT 3000 FT; WE WERE CLRED TO 2700 FT; PLACED ON A 30 DEG INTERCEPT HDG AND CLRED FOR THE APCH. THE FREQ OF 110.55 WAS TUNED AND IDENTED. MY INSTS INDICATED A NORMAL LOC CAPTURE AND THEN IN SEQUENCE A NORMAL GS CAPTURE. JUST AFTER LOC AND GS CAPTURE; A DIFFERENT CTLR'S VOICE ADVISED US THAT WE WERE LINED UP WITH THE RWY 17 COMPLEX. HE TOLD US TO TURN R AND REINTERCEPT THE RWY 18L LOC AND GS. WE ADVISED THE CTLR WE HAD RWY 18R IN SIGHT; WE WERE CLRED FOR VISUAL APCH TO RWY 18R. THE CAPT ADVISED THE CTLR THAT WE WERE TUNED TO 110.55 FOR RWY 18L AND STILL NOT GETTING PROPER INDICATIONS. WERE THEY HAVING A PROB WITH THE ILS FREQ? IT WAS TOO BUSY AND GOT NO RESPONSE. WE WERE HANDED OFF TO TWR AND MADE A NORMAL LNDG. AFTER LNDG I CALLED THE W TWR. I ASKED THE DUTY SUPVR IF THEY WERE HAVING ANY PROBS WITH THE RWY 18L ILS FREQ 110.55? HE SAID THEY WERE WORKING ON CHANGING THE FREQS FOR THE ILS'S BUT HAD NOT WORKED ON RWY 18L THIS DATE. STILL NOT SURE WHY WE HAD ALL NORMAL INDICATIONS ON LOC AND GS FOR RWY 18L BUT WERE LINED UP WITH RWY 17 COMPLEX. THE TWR SUPVR ADVISED HE WOULD CHK ON PROB; BUT HAD NO OTHER COMPLAINTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FLYING THE B737-200 FOR AN ACR. BOTH ILS'S WERE PROPERLY TUNED AND IDENTED. HORIZ VISIBILITY WAS REDUCED BY HAZE; BUT VERT VISIBILITY WAS GOOD AT THE APCH ALTS. THE RPTR'S ACFT WAS THE ONLY ONE THAT THE RPTR KNOWS ABOUT THAT HAD THIS PROB. NOTAMS SHOWED THAT THERE WAS TO BE WORK ON THE ILS'S THAT DAY. THIS CREW FLEW THE SAME ACFT FOR 2 MORE LEGS THAT DAY WITH NO PROB. SUPPLEMENTAL INFO FROM ACN 314664: APCH CTL STATED THAT WE HAD BEEN LINED UP FOR THE 17 RWYS. I SUSPECT THAT SOMEONE HAD CHANGED FREQ FOR ILS RWY 18L DURING OUR APCH. I CANNOT THINK OF HOW THE FALSE LOC ON MIGHT HAVE OCCURRED OTHERWISE.