A multiple laser head projector includes a sensor that senses the presence or absence of a laser beam from a first of the laser heads and signals a switching device to switch to a second laser head when a laser beam is not detected by the sensor from the first laser head. Thus, the multiple laser head projector may be utilized to provide continuous operation of the multiple head laser projector when one of the lasers fails. The multiple head laser projector may also be utilized for diagnostic testing of the laser heads, such as during start-up. Further, the multiple head laser projector may be utilized to signal the power output of the laser heads and thus the expected remaining life of the laser heads.