Look closely at the knob and you should see a small hole. Insert a straightened paper clip into the hole and feel around for what's called the clamp spring. It's actually a tab that rests against the switch shaft. While gently tugging on the knob, try to work the paper clip against the back of the tab. You'll need to be pushing your hand toward the dash which will be pulling the end of the paper clip forward which will, in turn, pull the tab away from the shaft enough to allow you to pull the knob off the shaft. To reinstall, simply push the knob on to the shaft.
It's not easy to do and patience is key!
