I realize this is an ancient thread, but I am a new crossfire owner and was researching speed control problems. While reading through the testing section of the Crossfire Service Manual, I came across this reference to a "cruise light" in Section 8P-7 , Pg 1501.
"Bring the vehicle speed back up above 35 mph and engage speed control. Press the OFF switch to turn OFF, (cruise light will be off). If the speed control did not disengage, the repair is not complete. Check for TSBs that pertain to speed control problems and then return to the symptom list."
Apparently someone at Mercedes or Chrysler thought there was a "cruise light".