Ebike/Escooter speedometer not working some help please!

netrate

Member
Region
Canada
I have included the front and back pictures of the display for the speedometer. The FULL/EMPTY of the battery charge works perfectly, BUT when the bike is throttled on the kickstand or in motion, the speedometer will not move from the ZERO

NOTE : I am not sure how this particular speedometer works having numbers on both sides of the ZERO.

I have included pictures of the front and back of the display. The wires for the speedometer are the PURPLE/BLUEWHITE wire. The speedometer not working does not effect the running of the ebike/escooter, but it does make it problematic if in the future I try to sell it. https://ibb.co/xsfdWbS
https://ibb.co/2S06X65

I worked on this Sunday afternoon for about 5 hours and still no closer to resolving it, but I think I might have some ideas.

I took off the face plate and removed the motor (see pic). https://ibb.co/jJGp2xQ

I have tested out the motor with a small button batter y (1.5V) and the needle moves - success - the motor works independently of the ebike.

What I have done :
  1. I have checked all wires for continuity - all are fine.
  2. Using the Multi-meter, the BLUE and the RED wire leading to the motor gets approx .800 volts each (see pic)
https://ibb.co/PwJjq91

3) When ONLY ONE wire (either the RED or BLUE) is connected to the motor, the multi-meter shows .800 approx (see pics)

https://ibb.co/PwJjq91

https://ibb.co/RSW1KFg

4) When BOTH WIRES connected to the motor, the voltage drops to ZERO (see pic)

https://ibb.co/G5BjtyH

5) When the motor is connected completely with both wires and the throttle is twisted, the voltage remains at ZERO and does not change

_________________________________________________________________________________________________________

Here is my guess work - but again I am really green at this :
MY GUESSES :
a) The voltage drops to ZERO when both wires are connected so the NEEDLE will remain at zero on the speedometer. This is what is necessary to ensure that there is no voltage going to the speedometer until the throttle is twisted.

b) Ideally, when the throttle is twisted - I am guessing here - some voltage should be going to the motor/speedometer (BUT it does not. The voltage remains at ZERO.)

Here is the the route the electrical takes:

i. This molex has 8 wires coming from it - the ones that are being used are the blue/white and the purple one below it.

https://ibb.co/2WVWh2F

ii. The male end of the molex goes to a small connector with a resistor

https://ibb.co/gtw698V

iii. The small connector with the resistor goes directly to the motor

https://ibb.co/3fw0Cy4

Continuity checked with all wires.
Any suggestions?
 
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