Defrost from the window to vents or floor does not switch

Hello, I'm Danny.

It sounds like you might be having a problem with the mode door actuator. It's a small electric motor that switches doors open and closed to direct air through certain ducts.I'm attaching picture steps below to help you diagnose the issue. Also, Here is a tutorial showing how to replace an actuator:

https://www.2carpros.com/articles/replace-blend-door-motor

The steps below are for your Hyundai Elantra. Notice step #4 showing how to test actuator to see if it switches to vent mode. Hope this hopes and thanks for using 2CarPros.

This blue light use to light up each option, but now it’s dead no power to any of the buttons.

Hello again.

First thing to check is the fuse for the A/C control switch. It's a 7.5 amp fuse. I've attached a picture of its location and circled in blue.Here is a tutorial on how to check/replace fuses:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Hope this helps and thanks again for using 2CarPros.

Danny-

The fuse is good and I checked all fuses and relays for power and all are good. Could it be a broken wire? I’m wondering if it’s easier to run a jumper wire to test the unit? Uh oh when I pulled the dash apart this is what I found:

Hello again..

Uh oh ! Was there a rodent infestation? Maybe a wire was chewed. When I get home tonight I will attach an A/C - heater wiring diagram.

Danny-

Yes, definitely a rodent infestation! Car sat for a year while recovering from a stroke.

Hello again.

Sorry to hear about you health issue and hope you are doing better. I've attached 2 pictures below of the heater and A/C system wiring diagrams for your Hyundai. I've cut the pictures in half so you can view them as larger.Here is a wiring check tutorial for you to view as well:

https://www.2carpros.com/articles/how-to-check-wiring

Hope this helps and let me know if you have any other questions about this issue.Thanks again for using 2CarPros.

Danny-

That diagram is not for the mode door actuator. Mode actuator is on the drivers side. Heat actuator is left of glove box.

Sorry, for the confusion, here is the correct location for the mode actuator and how to change it out. Check out the images (below). Let us know if you need anything else.