Hi from uk if as you say the brake fluid level is slightly above min ? then this is most probably the reason the warning light is on this light is also linked to both park brake when on and a visual warning via a sensor on the reservoir that brake fluid is low top reservoir up ? light should/will go off however! fluid level drops for two reasons = 1 fluid leak on b/system 2 or in your case the fluid level has dropped by displacement from reservoir to brake calipers/cylinders as the brake pads and/or shoes wear down to minimum safe thickness ? and if your car has brake pads wear indicators fitted to pads these sensors will put light on SO may i suggest you check your brake pads/shoes ASAP because if pads/shoes are very low ? you may not only damage the more expensive disc/rotors but pads may/will burn up resulting in brake failure with obvious results ? hope you heed this advice? it is for your safety and other drivers best wishes