On a hot weather car trip early of summer 2019, the A/C in my 2013 Santa Fe was turned on to Max and the blower to Max. Shortly afterwards (3/4 hour) the blower power diminished greatly and the cool air volume coming into the cabin also diminished greatly. There was not nearly enough cooling to satisfy us. The heat outside, while hot, wasn’t extreme.
I tried every which troubleshooting approach to fix the problem; including adjusting both blower and air temp settings, for dual (driver and passenger) sides. I could not fix the problem. If I left the A/C off for 20 minutes, the cooling and blowing power was restored, but only for another 30mins or so.
I am a retired engineer and used to work on my car maintenance/mechanics, in the days when cars were much simpler. I could tell that the cooling coils were not damage; later verification and attempts too replenish the condensor did not reveal any damage there. Hence my next best guess that some ‘device’ that controls the air volume via the air outlets in the cabin, was incorrectly closing the outlet flaps. The blower sounded like it was still working hard behind the outlets, but trap doors there appeared closed.
I just discovered a TSB document that was released by Hyundai in 2013 Nov. I believe it may be the solution needed for this problem. I certainly do not fee that it is major, nor do I wish to have the dealer mislead me down the wrong path to an expensive fix, if this blower PWM module replacement works. I will investigate further but anyone who knows if it is the correct fix, please let me know.