Hi, You should never be able to see any light coming out of a Creo's head. The write laser is invisible (IR - 830 nm), what you can see if there is a problem with your shutter (usually closed when any machine cover is opened or maybe you are using service key that override safety features) is a red spot on drum or plate - low power's focus laser beam.
So, if you don't use safety override key(s), that means shutter is stuck open and there is no chance to measure a laser as the beam calibration sensor is mounted on the back side of that shutter (for calibration of LV shutter should be closed).
Do you use Debris Removal Cabinet - UDRC?