E bike light not working after installation, help!
Discussion
Bought a cable to bridge the motor and bike light via Amazon and wondering if any of you can confirm if I’m doing something wrong as I can’t get the light to illuminate.
Bike is a Rockrider EST900 and I have a Brose T motor with a Brose all round display with headlight button.
The cable appears to only be able to fit into this top left slot, it has the opposite bobbly bits to the top right slot (anyone know what that is for? Rear light? )
The cable is plugged in, red to red, black to black attached to the Lezyne Macro Drive 1000 lights cable, twisted and taped up.
I then put the battery in the bike powered it up and pressed the headlight button. Nothing. Tried the button the light too that changes modes.
In the display settings I tried auto headlight and always on headlight, didn’t work either. Have tried removing and re seating etc nothing has worked even once. The headlight icon is coming on as it did before.
Can’t see how I could have possibly done something wrong here!?


Bike is a Rockrider EST900 and I have a Brose T motor with a Brose all round display with headlight button.
The cable appears to only be able to fit into this top left slot, it has the opposite bobbly bits to the top right slot (anyone know what that is for? Rear light? )
The cable is plugged in, red to red, black to black attached to the Lezyne Macro Drive 1000 lights cable, twisted and taped up.
I then put the battery in the bike powered it up and pressed the headlight button. Nothing. Tried the button the light too that changes modes.
In the display settings I tried auto headlight and always on headlight, didn’t work either. Have tried removing and re seating etc nothing has worked even once. The headlight icon is coming on as it did before.
Can’t see how I could have possibly done something wrong here!?


Just as a really simple thing to try first, give all the connectors and plugs a spray with some electrical contact cleaner or similar then put back together.
My Shimano EP8 threw a wobbler recently that was solved by doing the same so worth a try especially considering the ports should have blanks in them to seal them and yours look a little grubby suggesting they might not have done.
My Shimano EP8 threw a wobbler recently that was solved by doing the same so worth a try especially considering the ports should have blanks in them to seal them and yours look a little grubby suggesting they might not have done.
bobbo89 said:
Just as a really simple thing to try first, give all the connectors and plugs a spray with some electrical contact cleaner or similar then put back together.
My Shimano EP8 threw a wobbler recently that was solved by doing the same so worth a try especially considering the ports should have blanks in them to seal them and yours look a little grubby suggesting they might not have done.
Thanks - the ports did have covers on but will give it a try when trouble shooting later. My Shimano EP8 threw a wobbler recently that was solved by doing the same so worth a try especially considering the ports should have blanks in them to seal them and yours look a little grubby suggesting they might not have done.
I have confirmed that the bike is 6v 6w compatible, as is the light
stargazer30 said:
Hopefully not the case for your bike, but I know the Bosch systems, if you retrofit lights, the light port has to be enabled by a dealer before it will output any power.
I actually phoned decathlon earlier and asked - they hadn't fitted any before but weren't aware of that requirement - they are going to find out though and get back to me. The controller has a headlight button and the icon comes up etc when you press it.
WPA said:
Looking at this chart on Lezyne's site and it seems that light is not suitable for your Brose T motor,

Thanks for finding this, that is gutting! The wattage is showing as 7.5 there but says 6w elsewhere though, which according to decathlon is compatible. 
Might have to go through a different solution then. Not sure what to do with the light if that's the case.
Edited by joropug on Wednesday 13th September 15:25
Thanks again for all the suggestions - trouble shooting was successful, the weakest link was to blame. Me.
I thought I’d twisted the wires joining the cable and the light’s cable together enough but they had pulled apart, impossible to tell without unbinding the tape etc.
Now secured much better, cables tidied and voila - fantastic light.
Managed to get out tonight to test and snap these via my phone/drone:





I thought I’d twisted the wires joining the cable and the light’s cable together enough but they had pulled apart, impossible to tell without unbinding the tape etc.
Now secured much better, cables tidied and voila - fantastic light.
Managed to get out tonight to test and snap these via my phone/drone:





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