Tomberlin Vanish Stutters

[Ryandhill]

Hi,
I have a 2010 Vanish that has had a couple minor issues in the past. I am fairly electrical save but am missing schematics for this vanish or idea on the fix.
When the accelerator is pressed the cart sounds like it is grinding gears almost. However, having a bad battery previously made the same noise. I pulled 5 of the 8 this time and had them replaced. Changed out 2 of the battery cables.
The issue is still there.
I am reading 50. VDC from the lead + battery to the last battery in the loop.
I put the vehicle in neutral, its on jack stands still, and pressed the accelerator and it still barely moves. About the same speed no matter, high, medium or low electrical gear.

So first thought was check the fuses, they are all good.
Master fuse is good next to the motor controller.
I checked the motor controller and appear to be getting 25 VDC if I remember correct while the accelerator is pressed.
I know on the emerge series there is a fault light setup under the seat.. is there anything like that on the vanish.

The next step was to check the soilnoid beyond it just clicking and completing the circuit, which it is clicking. I took reading and saw the voltage drop while the accelerator was pressed.

I had a technician come out and say there is a speed controller more than likely in the motor he think it could be bad. How do I test this... I was unable to find a port for him to plug into.