i have no clue how your ezip is wired from factory but this is something somewhat easy to fit.
If originally there is no switch and no volt meter, you probably just have the 3 wires for the throtle. you would still need them with the new device.
For the switch, you would need to cut the turn on signal of the original controller. Dont try to cut the power to the controller since the switch will burn very quick. Usually it would be a full battery voltage signal so if you run it to the new switch directly, the other side of the switch can be used to turn on the controller and also to feed the voltmeter display. The voltmeter display negative return can be spliced on the black throtle wire unless the 5v is fully isolated, in this case you would need to run a negative wire from the battery negative side.
