WHILE PERFORMING THE MAIN LANDING GEAR TACH TEST ON AN AIRBUS A320 AFTER ALL THREE GEARS REPLACED; AN AVIONICS MECHANIC FINDS CONNECTORS 15GG AND 17GG HAD BEEN SWAPPED DURING VENDOR OVERHAUL.

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ACFT WAS IN ZZZ FOR ALL 3 GEAR REPLACEMENT. I WAS TO DO THE MAIN LNDG TACH TEST; TEST CARD #4R. WHEN PERFORMING TEST STEP D; 1 THROUGH 5 FOR 21GG #2 BRAKE; FOUND THAT #2 BRAKE WAS RELEASING NOT #1. WITH WIRES FROM TACHOMETERS TO MAIN LNDG DISCONNECT BEING WRUNG OUT PRIOR TO GEAR INSTALLATION; I KNEW THE PROB WAS NOT IN THE TACH WIRING. WITH FURTHER TROUBLESHOOTING I FOUND THAT CONNECTORS 15GG AND 17GG HAD BEEN SWAPPED DURING VENDOR OVERHAUL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HIS CARRIER HAS MADE CHANGES TO THEIR RECEIVING INSPECTION WHEN THEY RECEIVE AN OVERHAULED GEAR FROM A VENDOR. PRIOR TO INSTALLING AN OVERHAULED GEAR; AN INSPECTOR AND MECHANIC WILL WRING OUT AND VERIFY THE WIRE HARNESS IS PROPERLY ROUTED TO THE CORRECT BRAKE. ALSO; THE JOB CARD NOW REQUIRES ALL FOUR BRAKES HAVE LARGE PRESSURE GAUGES INSTALLED DURING THE WHEEL SPIN TACHOMETER AND BRAKE RELEASE TEST. THIS WOULD ALLOW MECHANICS TO ACTUALLY SEE THE HYD BRAKE PRESSURE DROP OR INCREASE TO EACH BRAKE AND HELP TO VERIFY THE ANTI-SKID FUNCTION ON EACH BRAKE IS WORKING PROPERLY. REPORTER STATED TO PERFORM THE WHEEL SPIN TACH TEST REQUIRES A MINIMUM OF FOUR MECHANICS. HE HAS ALSO FOUND THE ELECTRICAL HARNESS CONNECTORS TO THE ANTI-SKID VALVES REVERSED ON THE GEAR AFTER BEING OVERHAULED.