@Ryan If you are still troubleshooting, the probelm is rarely the WS500 and often a wiring issue. Having the wrong harness likely would not cause this isssue, but to test it is pretty straight forward. With a good multimeter set to ohms resistance
connect red to black lead and measure how close to zer it reads and use this value as your test zero
connect black lead to case ground
connect red to negative brush wire. It should read very near zero
connect your red lead to the other brush wire that is connected to your field.
It has to pass through the commutator and rotor windings, then back through the other brush to ground so, depending on the number of rotor windings you should read a resistance of less than 10 ohms, and sometimes very close to zero
When you have confirmed your polarity you can continue troubleshooting. Some ideas to try.
Remove the harness from the WS500. Does it still go to 100%? If so, and it does not go 100% when field is disconnected, its a wiring short in the cable or connector.
Remove all "panel" wires 1,2,3
Verify polarity on wires 5 and 6
Remove wire 8 , stator
verify polarity of wires 10 and 11
verify wires 12 and 13 are wired across the shunt
Now you have bare bones installation and if no wiring issues were found, try testing again.
If output goes to 100% with field wire 7 connected and remains at zero if removed, it is possible you may have a bad regulator.
Wakespeed handles warranty issues directly and their contact info is here.