Alright, next is the 3rd Speed Switch inside of the Control Handle Pod.
Remove the 4 small screws from the cover, you can the cover hang to the front or side, and test the voltage with a volts meter.
Stick the Negative probe into a Negative volts cable, and test for Positive volts at each wire of the 3rd Speed Switch.
You'll have to Raise the Drive Tire above the floor.

Twist the Control Grip while testing volts.
The 3rd speed switch might be bad, which means you might need to replace all of the small travel function switches.