Controller for Brompton G line is faulty

Hello,

Can anyone help me with the problem I am having?

I have 2 Brompton G line electric bikes, one works fine, one does not work with the following condition: When the battery is connected, the front and rear lights of the bike light up, however the indicator lights 2 and 5 on the battery are flashing. I have researched and found out that it is due to a fault in the controller. I have come up with a way to test it by swapping the 2 controllers (remove the G line that works well and install it on the faulty one). The surprising result is that the G line no longer shows the warning light and works fine. I am sure that the controller is faulty.

Is there a way to replace it with a new controller? Is there anyone who can help me buy a new controller? And where to buy it?

I cannot bring the whole bike to the UK for repair, because the shipping cost is quite large and not feasible. There is currently no Brompton Gline electric store in my country so it is impossible to bring the bike in for inspection.

My G line bike is manufactured in 12/2024. I accept to buy a new controller for convenience. Does anyone have a spare controller, I will buy it back by asking relatives in the UK to pay for it.

Thank you