Still having problems with left stepper motor jerking

Still having problems with left stepper motor jerking. I know to check wire connections, I have the mini bus bar blocks, have connected and re-connected, and now I hard wired just to check. I have no resistance while turning motor, should be a loose wire, not so if they are hard wired. I have the Pro Controller the nice all in one.
Could I have a bad stepper motor controller?
Any help would be greatly appreciated.

I forgot to ask, does anyone know what stepper driver Brandon used in that All in one?

Perhaps you could switch the wiring between the left and right stepper motor. Should see if the problem moves or not - if not, I think it’s the left stepper, if it moves, then wiring. good luck.

Have you opened the controller box to check connections?

@Jack_Daugherty These are the driver boards in my controller, which is the simple controller. They look to be a MKS board, but I am not certain. If you open the controller box, be careful as there is not a lot of extra wire to work with. Just make sure power is off when checking connections.

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Well guys found the problem, like most support answers are, check connections.
I found my Y with limit switch plug going into the all in one had a bent pin. Repaired and running strong again.
Thanks guys for the help and support.

@Bob_Martin Great news! Those terminal blocks are not the greatest either, but I think you said you already bypassed those. Now you can get to cutting.