A CONTRACT MAINT MECHANIC; DUE TO A MISCOM; REPLACED THE #1 ENG OIL SCAVENGE FILTER ON A B737-700 AND DISPATCHED THE ACFT. IN ACTUALITY THE FUEL FILTER WAS CLOGGED.

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I WORK FOR ACR X AND WE DO CONTRACT MAINT FOR SEVERAL ACRS HERE IN ZZZ. AT APPROX XA00 LCL TIME ON FEB/XX/08; I RECEIVED A CALL FROM ACR Y THAT THEIR ACFT X HAD A FILTER BYPASS LIGHT DISPLAYED FOR THE L ENG. I CONTACTED ACR Y MAINT CTL; WHO HAD ALREADY SPOKE TO THE CAPT ABOUT THE PROB. ACR Y MAINT CTL HAD DIRECTED ME TO INSPECT AND CHANGE THE L ENG OIL FILTER AND HAD FAXED ME ALL THE MAINT MANUAL INFO. THEY ALSO SUPPLIED ME WITH AN OIL FILTER KIT FROM THEIR STOCK. I REPLACED THE L ENG OIL FILTER AND FOUND NO CONTAMINATION. WE RAN THE ENG AND FOUND NO LEAKS. AS PER MEL THE ACFT WAS DISPATCHED. AT APPROX XE00 I RECEIVED A CALL FROM ACR Y MAINT CTL AGAIN; AND I WAS ASKED WHICH FILTER I HAD CHANGED. I RESPONDED THAT IT WAS THE L ENG OIL SCAVENGE FILTER; JUST LIKE THE MAINT MANUAL PROCS THAT THEY HAD FAXED ME EARLIER. AT THAT TIME I WAS INFORMED THAT THE FILTER CLOGGED LIGHT WAS FOR THE FUEL FILTER; NOT THE OIL FILTER. A DIFFERENT FLT CREW HAD DISCOVERED THE DISCREPANCY. THE ACFT HAD BEEN DISPATCHED WITH THE INCORRECT MEL USED. WHILE WORKING UNDER THE GUIDANCE OF ACR Y MAINT CTL; I HAD ASSUMED THAT THEY WERE CORRECT IN EVALUATING THE ACTUAL PROB AND WHICH MEL TO USE. THE WORDING FOR THE FUEL FILTER BYPASS LIGHT ON THE P5-2 PANEL IS VAGUE. IT DOES NOT INDICATE FUEL OR OIL. THE WORDING FOR THE OIL FILTER BYPASS LIGHT IS DETAILED; SPECIFYING OIL. I BELIEVE THAT THE LENS FOR THE FUEL FILTER BYPASS LIGHT SHOULD BE MODIFIED TO INDICATE FUEL. THIS WOULD REMOVE ALL DOUBT ABOUT WHICH FILTER IS BYPASSING AND PREVENT THE SAME KIND OF ERROR IN THE FUTURE.