I suspect that you have two separte issues: water leak, heater control fault
I advise you investigate the heater flap operation to ensure the flaps are moving on demand.
The door membrane is not fully sealed so water leaks in between the door interior panel and metal work.
The N/S/F door pad (panel) needs to be removed for inspection of the membrane seal (foam, metal or plastic panel depending on model/year)
Close doors and carry out water test (hose pipe over both doors until leek appears) this will show which door has the issue.
If metal panel remove all retaining bolts reseal seal strip on panel (mastic) or replace panel with new item, best result change panel.
If foam panel or plastic reseal sealing face with mastic or replace panel if ripped.
Carry out second water test to proof repair.
Refit door pad.
Note when doing water test only access vehicle through opposite side to inspect for leaks, easier if you are in car and have someone on the hose.