A RETURN LAND IS MANDATED BY THE FLT CREW OF A B737 WHEN IT WAS DISCOVERED AFTER TKOF THAT THE MEL PROC USED WAS NOT AUTH FOR THE ENG REVERSER PROB AND MEL PROC USED AT ZZZ; US.

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AT XA47Z I RECEIVED AN ACARS MESSAGE THAT FLT NUMBER HAD PUSHED OFF THE GATE AND THE #1 THRUST REVERSER LIGHT WOULD NOT EXTINGUISH. I CALLED OPS TO ASK WHAT WAS GOING ON AT THE GATE. I WAS TOLD THE JET WAS PUSHED INTO THE TXWY AND MULTIPLE MECHS WERE WORKING ON THE ACFT. WITH THAT INFO; I CONCLUDED THE REVERSER WAS BEING LOCKED OUT. AT THIS POINT; I CONTACTED THE CREW VIA ACARS AND ASKED 'DO YOU WANT TO ADD 78-1?' AFTER A COUPLE OF MINS; THE CREW RESPONDED 'YES FOR 78-1.' AFTER THAT RESPONSE; I FURTHER CONCLUDED THAT MAINT HAD FOLLOWED SP #78 AND GAVE TIME AND INITIALS FOR THE MEL. SINCE THE AIRPLANE WAS OFF THE GATE; I ADDED 'CALL ME IN YYY FOR A TRACKING NUMBER.' A FEW MORE MINS PASSED AND I GOT A CALL FROM MAINT CTLR IN ZZZ. THE MECH ASKED IF FLT NUMBER WAS FLYING. I SAID 'YES; WHAT'S UP?' HE SAID 'IT NEEDS TO RETURN; IT SHOULD NOT HAVE DEPARTED.' CONFUSED; I CONTACTED THE CREW VIA THE RADIO AND TOLD THEM TO AIR RETURN. AFTER REVIEW OF THE LNDG WT; I CONTACTED THE CREW ON SHORT FINAL TO HAVE THEM GO AROUND AND BURN OFF FUEL TO GET TO A SAFER LNDG WT. THE FLT WAS SENT TO HOLD S OF THE FIELD AND LANDED ABOUT 40 MINS LATER WITHOUT FURTHER EVENT. IN MY OPINION; SOME CONTRIBUTING FACTORS: 1) CONCLUDING MAINT WAS DEALING WITH THE ISSUE. 2) NOT ASKING THE CREW PROPER QUESTIONS. 3) TRYING TO DO THE RIGHT THING TOO QUICKLY. 4) NO EFFECTIVE COM FLOW BTWN MAINT/DISPATCH/CREW. 5) IN THIS CASE; I BELIEVE ACARS HINDERED MAKING CORRECT DECISIONS. 6) MECHS LEAVING AN ACFT THAT WAS NOT SAFE FOR FLT. POSSIBLE SOLUTIONS: 1) BRING THE ACFT BACK TO THE GATE IF THE PROB IS THAT SERIOUS; DON'T TRY TO FIX IT IN A TXWY. 2) COMMUNICATE; COMMUNICATE; COMMUNICATE. 3) SLOW DOWN. 4) COMMUNICATE VIA RADIO WHILE IN THE TERMINAL AREA.