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Schwinn Missile FS Throttle connection to new SPD-SD600 controller

 Ordered a new controller but the connectors need to be changed. I want to make sure I'm connecting the right wires.  The throttle side wiring has wires colored Red, Yellow, and Green.  On the new controller, the throttle wires are Red, Green, and Black.


I'd normally assume Red/Red, Green/Green, Yellow/Black, but I looked at wiring diagrams for other bikes and saw some connections that muddied the waters, so to speak.


Can you please confirm the wiring connectivity?  Thanks!

I found an electric scooter throttle with Red, Yellow, and Green wires and tested it to determine what the functions of the wires are and found that Red is +5V input, Yellow is ground, and Green is the output signal wire.

The throttle I tested is not from a Schwinn Missile FS so I cannot 100% confirm that your throttle and my throttle are wired identically, but chances are very high that they are. I also found an old throttle to controller service bulletin that showed Yellow as being the ground wire on three wire throttles.

I found a way to non destructively test the throttle's wire colors. With a variable DC power supply I applied +5 Volts to the throttles Red wire. Then I set my multimeter to DC Volts and connected its Black ground probe to the power supply's Black ground output, then with the multimeter's Red positive probe I tested the Voltage of the throttles remaining two throttle wires. What I found was the throttle output signal wire has around +4.5 Volts present, and its ground wire had around +5 Volts present. I tested a standard three wire throttle with Red, Black, and Green wires to determine this, then I performed the same test on the throttle with Red, Yellow, and Green wires and got identical results. So next I took an educated guess that the Yellow wire was ground and tested the Red Yellow Green throttle with +5 Volts to Red, Ground to Yellow, and I got the expected 0.85 through 4.2 Volts output (depending on position of throttle) from its green wire.


I would say that chances are very high that the yellow wire on your throttle is ground. To absolutely 100% confirm this would require testing the throttle as described above though.


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