HVAC Controller melted switch 2014 kia soul

Mom complained to me recently of the “AC not working” in her car. Not knowing exactly what this meant I went out to check it out myself. The blower seemed to be working on mid-high only (not max). The interesting part about that is you had to hold the switch halfway between 3 and 4 to get it to work. The light for the “max AC” light didn’t come on either when I pressed the button, although I verified the temp switch (blend door function) works properly. I checked the fuses, good and I verified the compressor clutch was spinning.
My focus was getting the blower working first since colder weather will be coming up. I initially went after the blower motor resistor but after failing to get the glove box off to get to it decided to play with the switch some more. It became pretty obvious to me that was where the issue was or perhaps a result of the issue.

I pulled off the fascia around the radio and hvac controls, disconnected it and took it inside for inspection. The connector for the blower switch was scorched. When I opened the module I found the socket wasn’t sitting flat as if it was pushed out of place. The plastic around one side of it was melted and when I stripped the switch all the way found more melted plastic that was covering the metal contacts that the wiper moves across when you turn the switch. There was also a portion of the surrounding plastic that had bubbled up in a way that looked like it would prevent the wiper from making contact on the high setting. I got to work with a dremal and was able to restore the recirculation function along with 3 of the 4 blower settings. However the AC switch (light) still won’t turn on. I have a feeling this is also fault of the HVAC control module because it went at the same time as the blower settings did.

The obvious thing to do here is replace the module but what caused this thing to melt in the first place? Upon checking the cabin air filter it was EXTREMELY dirty. I already replaced it. Maybe it caused the blower motor to struggle, IDK a guess on my part.

I pulled this picture off ebay btw to let you know what I’m talking about. I should have taken pictures of the insides of the switch, but I was in a hurry to get it back in the car.

A dirty air filter restricts the air flow to the fan/motor.

Fan laws dictate when a fan/motor see less air, the fan/motor do less work Which means the motor draws less current.


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I’ve got nothing to add except make sure someone didn’t put too big a fuse in there so it didn’t blow when it should have. Maybe you can find a used unit. Gotta be fairly expensive part.

Is that connector located in the blower’s air path? If so, the clogged air filter might disturb its cooling. Home furnace blower motors can be damaged if the filter clogs b/c the motor is cooled by the air flow.