I had the same issue and could find no answer anywhere for this. So, I figured it out -- here is the fix-
ISSUE:
2015 Genesis Sedan AWD. My son drives this now. One day, the passenger seat would not recline, but would continue to move forward. Eventually, the seat was all the way forward (we will call this incline) where nobody could sit in it because you are bending forward. All other features on the switch panel on the side of the seat worked (seat up / down, forward backwards and lumbar). All worked except recline. This clearly had to be something in the switch. The replacement part cost is $150 but this fix is no cost.
FIX:
The fix was pretty darn easy I must say. There was some issue in the actual plastic knob that was causing the switch to not hit the button on the actual circuit board. The fix was getting to the actual circuit board and manually pressing the white button and then it worked. I have a full video below, it is a little rushed, as I was doing it myself but explains what you need to know.
So, for anyone in a crisis that needs to fix a stuck seat, this is a quick fix. You can then put everything back together when you fix it and try again. If the button still does not work it is clearly something with your plastic knob, where the plunger is not making contact with the board. You will see on the actual function knobs (the plastic knobs that the users will touch and move) there are small white plungers that go up and down, that make contact with the buttons on the circuit board. When a user moves a knob (forward or back, or up and down) this pushes the plunger out of the socket, and then pushes the button on the circuit board, which then activates the seat to move. Sometimes if a knob is out of line or not pressed in all the way the plunger wont reach the button to make contact. This is not electronic, they are small plastic plungers like little white pegs, so be careful when you pull your knobs off that non of them fall out.
Here are the steps to fix, the video is below
Unscrew the plastic liner around the seat. Pop cap off the first one closest to center console, then pop off that liner. Then you will see a second screw, unscrew that one.
Then you want to remove the entire switch / control unit by unscrewing 3 screws.
Once you unscrew those, unplug the control unit at the socket
Then you will have the raw enclosure that still has the knobs on it. Your goal now is to get to the control unit by itself. To do this, pop but function knobs off (only 2 of them, the circular lumbar just slides off) then unscrew the 5 screws on the black casing (see video)
Then using a small flat head screw driver, pop out the black tabs (see video) and the trim around the black casing also. Just stick your screw drive in on top of the tap, ,press down as you pull the panel outwards and it will pop out. Do this all the way around the unit, on the black plastic casing as well as the trim of the car (this will be whatever color your car trim is).
Then you will have the raw circuit board. All you need to do is connect it back in its raw state and press the white buttons and all should work and you can get your seat back to were you want it.
Then, you can either leave it as is, or put it all back together and hope your knobs will function as they are supposed to.
Here is the video, sorry if it sounds rushed.
