The cruise lever seems to have 5 different things it can do,
So far I've found:
Switch on the dash enables/disabled cruise mode,
Pushing the lever down while driving sets the cruise speed and activates cruise,
Holding the lever up increases the cruise speed,
Pulling back on the lever deactivates cruise.
I can't seem to get the lever to do much else, like temporarily deactivating cruise or re-activating cruise after having previously set the speed.