What is this black and white wire for?

[ampy]

Hi All,

I was looking at the cabling on my ebike controller and i saw a black and white wire joined together.
I disconnected it, powered on the bike, the display came on but no power to the motor, then the display went off and I thought I had damaged the bike. But I reconnected the wire and it seems fine now.
Does anyone know what it's for?

Thanks

 

[Bonzo Banana]

Hi All,

I was looking at the cabling on my ebike controller and i saw a black and white wire joined together.
I disconnected it, powered on the bike, the display came on but no power to the motor, then the display went off and I thought I had damaged the bike. But I reconnected the wire and it seems fine now.
Does anyone know what it's for?

Thanks

I've seen two wires like that. One is the speed restriction wire on some controllers to limit the assistance speed to the legal limit but the more common connection I think is to reverse motor direction which if you have a geared hub motor rather than direct drive hub motor won't actually reverse the direction as the clutch plate will dis-engage and prevent the wheel rotating.