IF YOUR WIRING IS CONNECTED PROPERLY AND YOUR MOTOR RUNS WITHOUT THE SPEED CONTROLLER BEING TURNED ON THEN YOU HAVE A PROBLEM WITH THE SPEED CONTROLLERS MOSFET SWITCHING TRANSISTORS BEING SHORTED .DIODES ARE SHORTED WITHIN THE MOSFET TRANSISTORS.

EXCESSIVE HEAT ON THE SOLDERING IRON HELD ON WIRING CAN CAUSE THE ATOMS THEY ARE IN THE WIRING COPPER OR SILVER TO VIBRATE CAUSING A CURRENT FLOW .EXCESSIVE CURRENT CAUSED BY HEAT CAN DAMAGE THE ESC.

THATS WHY THEY SAY DONT SOLDER FOR TO LONG ON THE WIRING AND IF YOU CAN USE CLIPS AND NOT SOLDER ,LIKE THEY DO ON COMMERCIAL AIRCRAFT NOTHING IS SOLDERED EVERYTHING IS CRIMPED.

JUST A THOUGHT .I HOPE IT ALL WORKS OUT FOR YOU.