The fuser assy. has the jam actuator/rod/flag that trips the light sensor (
Photo Interrupter)
mounted on the left side of the fuser. Sensor tabs break off and the sensor falls off and interferes with the movement of the flag. Obviously a replacement fuser would fix this problem but I was able to use super glue to hold the sensor back in correct position. This also applies to several other machines that use this fuser like clj 2700, 3600, 3800, etc.