DIY solution to broken light switch on SC-E5000 display

[GabiG]

Hi!
My button to turn on the front light has recently stopped working. The workshop's service report confirmed the wiring is correct but the button on the display is broken.
If ChatGPT is right, then I can't bypass the light switch directly to the motor, as the motor won't give power to the lamp if the display button doesn't tell the motor to do so.

Pretty new to this so apologise for badly explaining or confusion.
I want to find a DIY solution to use the motor as energy source for the front lamp instead of buying a completely new display only for the broken button.

Bike info:
Mid motor Shimano STEPS DU-E6100
Display SC-E5000

Any tips are welcome!

 

[fill]

Did anything change/happen before failure? for example If additional aftermarket lamps have been added its possible that has exceeded the amp handling capacity of the switching components??

Depending on the lamps operating voltage Switching the battery voltage to power the lamp either directly or via an appropriate voltage dropper should be do-able. However the easiest solution would be to use a supplementary clip/bolt on lamp with its own battery imho,

 

[amberwolf]

Well, your motor is not likely providing power to the light nor be able to do so.

The power would come from the battery.

The display itself probably manages the lighting via a tiny transistor that is commanded to turn on or off by the MCU in the display when it detects the button press.


If the button (switch) on the display has actually failed, it should be relatively simple to replace the switch that is under the button, either directly with a new one, or if they used something custom that isn't available, simply add wires to the pads on the board on either isde of the switch, and add an external momentary switch that you then press to toggle the light on or off. This is the simplest repair option.


If the display's transistor has failed, then it could be replaced, but it is probably a tiny SMT part and difficult to do. So bypassing it by adding wires to the points the transistor was connecting, and running those out to a non-momentary switch (toggle, button, rocker, whatever) would let you turn the light on, still using the display's internal systems to supply the power itself from the battery just like before. This is the middling-complex repair option.

If the display's itnernal power source to run the lighting has failed, and the button and transistor both work, then you'd have to fix or replace that supply. This is the most complex repair option.


If you don't want to deal with any of that, then you need to know what voltage the light requires to operate, and how much current (amps) it requires when operating. ONce you know those, you can then find a DC-DC converter that will output that voltage and can supply at least that many amps, and will accept your battery's voltage as input. This goes between your bikes' battery and the light, and you can add a non-momentary switch in between the battery and the DC-DC to be able to turn the light on and off. This is the 2nd-simplest repair option.

 

[GabiG]

Did anything change/happen before failure? for example If additional aftermarket lamps have been added its possible that has exceeded the amp handling capacity of the switching components??

Depending on the lamps operating voltage Switching the battery voltage to power the lamp either directly or via an appropriate voltage dropper should be do-able. However the easiest solution would be to use a supplementary clip/bolt on lamp with its own battery imho,

Nothing electrically has been altered prior to the failure. My guess is the handlebar was roughly handled and the button got a slam.

I do agree that another lamp with an independent battery source is the easiest solution. However, there is an itch to try and solve it without resorting to yet another thing to charge or replace batteries on.

Thank you so much for the reply fill!

 

[E-HP]

Nothing electrically has been altered prior to the failure. My guess is the handlebar was roughly handled and the button got a slam.

I do agree that another lamp with an independent battery source is the easiest solution. However, there is an itch to try and solve it without resorting to yet another thing to charge or replace batteries on.

Thank you so much for the reply fill!

Have the shop replace the parts. When you buy a prebuilt ebike, you have to resign yourself to being handcuffed to using factory service for even simple things. amberwolf’s suggestion on using a buck converter makes sense, if you can figure out how to access battery pack voltage.