Unable to turn off fan

So I was driving on the interstate for 45 minutes the other day with the fan on the lowest speed no AC and suddenly for no reason at all the fan ramped up a notch or two with no change in the temperature/fan speed display. I was unable to turn it down but could turn it up. Got to my destination, shut the truck off, let it sit over night, same issue. Started the truck up, the blower is turned off but blower is still blowing air. Has anyone ever had this happen?

 

Yeah it’s called auto mode

 

Even when the auto light is not illuminated? Good thought but I never use auto mode. Seems like the issue finally resolved itself on the third start. The only change I can think of is I turned the AC on for a bit on the drive home.

 

If recirculation is turned off, fresh air is forced (allowed) in, you'll notice more highway speeds and drastic temp differences. I prefer to have this, I use it a lot in the mild Fall and Spring seasons, unless I need AC to remove moisture.

 

I seem to remember you can change a few parameters around this auto fan control using techstream, it may be worth reading up on those options and asking dealer to set them for you if you don’t have techstream.