Hi Roy,
1. It doesn't contain a switch that applies full throttle to the motor system as the GM Pedelec sensor uses a series of magnets to produce a pulsed output.
The frequency of the pulses varies according to the pedal rpm
(cadence) and the controller provides variable power to the motor based upon the actual pedal rpm:
If you slip the chain off the chainwheel
(or ride in a very low gear) you can actually control the speed of the motor just by varying your cadence.
2. Although it uses a Hall sensor, the pulsed output means that it cannot be directly used to control the operation of the thumb/twist throttles.
However, it should be possible to use the output from the sensor
(in conjunction with a 555 timer chip and a few other electrical components) to activate a 5V relay that would only connect the throttle signal to the controller only when the pedals were being turned:
I don't know if the above circuit will actually work, or whether it might need a diode on the Hall sensor output that would only allow the high voltage pulses to reach the 555 timer chip.
Unfortunately, it is not quite as simple as you had originally envisaged.
Alan