DURING 2 ILS APCH ATTEMPTS; BOTH LOC AND GS OFF FLAGS SHOWED JUST PRIOR TO THE OM AND THE IDENT COULD NOT BE HEARD ON BOTH THE FO AND CAPT'S RECEIVERS OF A DC-9 TYPE ACFT.

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AFTER A ROUTINE SCHEDULED FLT FROM ORD TO DTW; WE WERE BEING VECTORED FOR AN ILS APCH TO RWY 21R AT DTW. THE ATIS GAVE THE WX AS 300 FT OVCST AND 1 MI VISIBILITY. AFTER INTERCEPTING THE LOC WE WERE CLRED FOR THE APCH. APPROX 12 MI OUT FROM THE RWY; THE FO'S GS AND LOC 'OFF' FLAGS CAME INTO VIEW (HE WAS THE PF). A FEW SECONDS LATER; MINE (CAPT'S) ALSO WENT OFF THE AIR (ILS LOC/GS). WE BOTH TRIED TO GET THE MORSE CODE IDENT. BUT BOTH NAV RECEIVERS SEEMED DEAD. WE ASKED APCH CTL TO TAKE US OFF THE APCH SO WE COULD CHK THE THING OUT. WHILE BEING VECTORED; BOTH OUR NAV RECEIVERS CAME BACK ON; ALSO WITH THE MORSE CODE IDENT. WE BOTH FIGURED THE GND SIGNAL HAD BEEN INTERRUPTED; EVEN THOUGH THE CTLR HAD SAID THAT HIS EQUIP WAS WORKING OK. WE ELECTED TO TRY ANOTHER APCH. AGAIN; JUST OUTSIDE THE OM BOTH OUR NAV RECEIVERS WENT OFF THE AIR. I ASKED TO BE VECTORED TO HOLDING; WHILE I CONTACTED OUR DISPATCHER. DURING THAT TIME I TRIED OTHER ILS FREQS; AND GOT THE SAME 'OFF' FLAGS AND NO IDENT. OCCASIONALLY; THEY WOULD COME BACK ON THE AIR BUT GO OFF. WE DECIDED TO DIVERT TO CLE WHERE THE WX WAS VFR. A NORMAL APCH AND LNDG WAS MADE THERE. WHERE THE ACFT WOULD REMAIN OVERNIGHT FOR MAINT. DURING OUR DILEMMA; I TOLD OUR LEAD FLT ATTENDANT OF OUR PROB; AND THAT WE WERE GOING TO CLE. SHE MADE A PA TO PAX TO TURN OFF ANY ELECTRONIC EQUIP IF IT WERE BEING USED. WE HAD NO FURTHER PROBS. I AM STILL BAFFLED ABOUT THIS; AS THE DC-9 USES 2 SEPARATE ILS NAV RECEIVERS. I AM STILL WONDERING IF A PAX DID HAVE SOME ELECTRONIC DEVICE ON AT THE TIME WE MADE OUR APCHS TO DTW.