Looks like you have been having issues with this system since 2014?
Float circuit is "fail safe", ie it triggers if the wire is broken or the sensor is disconnected etc.
Quite common on vehicles for safety related warning or protection systems.
The float will probably have a magnet in it.
The sensor will have a reed switch that is held closed by the magnet when the float is up.
When the level drops the magnet drops down away from the switch and the switch opens.
The pcb then turns the light on.
A "cheap and cheerful" repair I have done in the past is to use the normally closed contact of a small relay to operate the light.
Looks like one side of the warning lights are connected to a common ignition or ground.
Solder a wire to this common and connect to the common terminal on the relay(30?).
Cut the pcb track on the other side of the brake fluid light and solder a wire directly at the light and connect to the normally closed relay terminal(87a?).
Connect one relay coil terminal(86?) into the ignition wire for the module.
Disconnect the float signal wire from the module and connect to the other relay coil terminal(85?).
Use a relay with a diode or resistor protected coil to protect the reed switch from inductive spikes when it switches the relay off.
The relay will be held on with the fluid level correct. Normally closed contact open - light off.
The relay will turn off when the fluid drops. Normally closed contact closed - light on.
The light shouldn't flicker with the correct fluid level, but may flicker at times if the fluid level is getting low?
You could call this an early pre-warning?