Okay, I attached wires to the grey and black PAS wires and the blue throttle signal wire, all within the controller, with leads coming out for testing purposes. Before further testing I checked the voltage of the throttle signal. With the throttle resting it was about 0.9V and the motor started running at about 1.1V when the throttle was advanced, topping out at about 4.0V at full throttle.
Then I verified that everything worked normally, that is normally for a 2017 controller that has the throttle/pedal issue.
Then I shorted the grey and black PAS wires together and retested. As expected the PAS system no longer functioned, and when set to PAS 0 the throttle had full range while pedaling.
So success for the initial testing! Just for disclosure, these tests were done in the house with the controller wires all hooked up properly but the controller was not physically installed. Also the chain and chain ring were not installed so the back wheel did not turn, and hence no speedometer, so the Bafang did show the expected error 21.
Now I'm ready to complete the project by installing a transistor between the grey and black PAS wires and a resister between the blue throttle signal wire and the transistor. Problem is, I have no idea what to purchase (I have no experience or knowledge in this area). Fechter, can you provide me with the details of exactly what to purchase, and where? Will I be able to just take the part specs in to a local Radio Shack or do they need to be ordered from someplace like Mouser?
Thanks in advance for any additional help. I am excited to be able to make this controller work the way it should, at least the way I think it should.