Not sure where the NC picks up the coolant temp. If you can find the sensor that does that, its likely shorting somehow or going to ground as wet which would make the bike think its too hot. So you would get fan,overtemp and engine light. Might also overly lean the fuel if it thinks the engine is really hot. Would also make it hard to start.
I am no expert on the NC internal workings but have experienced the above on other bikes. Find that sensor and dry it out!