First things first, yes, the water leak issue will destroy the blower motors and sometimes the resistors, but unless you've had water in passenger compartment floorboards thats unlikely the issue. I would start by checking the main ground, negative cable to the battery and where it attaches to the car, look for corrosion, take the cable off and clean around where it seats and use some dialectric grease when reassembling. You can check the alternator connections as well.
Merry Christmas by the way.
