Why do my fans work on all settings except 3?

SELFLESS71

MEMBER
2013 HYUNDAI SANTA FE
3.3L
V6
2WD
AUTOMATIC
125,000 MILES

No problems with A/C or Heat, or Fans ever before. One day it was hot out and I tried to turn the A/C up, so no air coming from the vents at all. I thought it broke, but I turned it up higher, and it was fine. My vents blow air fine, no strange noises, nothing. I used to be able to wiggle the knob a little then it would work, but now setting number 3 just doesn't exist. (It's my wife's favorite setting apparently). From what I know if it were the resisters then all of the lower settings would stop working. But every setting works except for number 3. What do I do to fix this?

Friday, July 28th, 2023 AT 8:59 PM

1 Reply

AL514

MECHANIC
5,499 POSTS

Hello, yes surprisingly this system still has a current limiting resistor for the blower motor speeds, but if you were able to wiggle the control knob it might be an issue inside the controller and not the blower resistor. But I think they are cheap enough you could swap them out and see if that changes anything. I'll post a diagram with its location.
Diagrams 1-3 are for testing the Blower Motor resistor if you would like. Diagrams 4, 5 are the lower dash cover on the passenger side. And 6, 7 are for replacing the Blower resistor itself.
But you can see the path that current flow takes in the 1st diagram. The resistor is on the Ground side of the Blower Motor, and it limits current flow before going into the blower motor speed switch, and then to Ground. So, the issue can be either the resistor or the controller switch in this case. If you have a rear HVAC system, the rear blower motor is controlled a completely different way.

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