Tommy, I found an older post too. Check this out - did you try any of these things?
https://www.golfmk7.com/forums/index.php?threads/blower-motor-changing-speeds-on-its-own.358377/
https://www.golfmk7.com/forums/index.php?threads/blower-motor-changing-speeds-on-its-own.358377/