Where does one get the wiring diagram

Http://www.icare-jmb.com/Documents%20partages/eclates/pride/scooters/BASE-GOGO.pdf
This illustrated parts breakdown will allow you to follow the wiring harnesses and check and test all the interconnects. This manual will allow you to remove covers and locate parts. Some basic problems can be solved by checking for loose, disconnected, burnt or damaged wiring and connectors. This manual will also give you part numbers. It is best to check with customer service before ordering parts since there are parts changes based on Model and serial number.
Just as a point of reference, most issues for this model can be found in the electronics assembly console, the plugs at the controller and the battery box connections and HIDDEN fuses. B7 page 30 is a good example of a hidden fuse on the battery box that is sometimes burnt out. E3 page 28 is another hidden fuse. Hope this helps.