try unhooking the pad sensors, blow them out with a air source, or unplug them on a dry day and let them sit for a while and dry out. the connections getting wet may have caused an issue with the resistance values of the sensor. they operate of a resistance value when the pad cuts into the sensor it opens the circuit and turns the light on so the water might have messed with the resistance. i was a certified mercedes technician for 5 years at a dealership and we dealt with pad sensors all the time