| you should not have to reset it, it should automatically detect they are fine, well atleast that is the way with e30's. On the e30's, faulty brake light warning is probably, wrong wattage bulbs, dirty connections or faulty bulb tester, it is normal for the brake light warning to be on before you first press the brake pedal.
Make sure the washer fluid float can move freely in the tank, the float has a magnet in it which pulls to wires together when the float is high, this closes the circuit and turns the warning light off, you will see how it works when you look at it. Pull the plug off the level sensor and use some wire to jump the pins (create a closed circuit), if this turns the warning light off then the sensor is faulty, but you could just leave the jumper wire in place if you dont want to replace the sensor |