Not all throttles are wired the same, however, most throttles and controllers use black as the negative wire even if there are multiple black wires. If the motor is operating erratically that could be caused by a poor connection between the sensor and wires or in the connector between the throttle and controller.
Sure Thanks for your kindly advised, I wish to ask 1 more question, is it possible to change 36V battery BMS, or have no choice must change battery pack? or any measurement to ensure my battery is still working?
BMS boards can be replaced on most lithium battery packs because they use wires that are soldered to the batteries. An online search for "how to test 18650 lithium battery" will bring up many videos and pages showing how to test the individual batteries in a lithium battery pack.