It is difficult to diagnose the problem without seeing how all of the parts and the battery pack are wired together.
Would you able to take and attach photos of the wiring connections between all of the parts so we may have a look and see if we can notice anything that may be causing the problem?
I recently purchased the SPD-482000a. I'm using the THR-115k.The motor is a 800watt brushed.
Everything looks to be connected correctly as per your diagram.If I disconnect the 3 throttle wires only and still have the yellow and thick red connected.
It reads 49 volts to the motor.Hence my problem that full power is running straight through controller. Do you have any suggestions what the problem is?