Disconnect wires from the front brake.
Now see if the rear brake actuates the light correctly.
Do the same to the rear brake and see if the front brake actuates light correctly.
Next step is do you have aftermarket Clutch and Brake levers.
Some aftermarket levers need the nub adjusted with a file to work correctly
Now see if the rear brake actuates the light correctly.
Do the same to the rear brake and see if the front brake actuates light correctly.
Next step is do you have aftermarket Clutch and Brake levers.
Some aftermarket levers need the nub adjusted with a file to work correctly