HP LaserJet 9000 Printer series - Manual (Page 7)

ENWW Interpreting light patterns 7
Interpreting light patterns
Figure 1. Location of LED light
The user LED light, located on the front of the device, indicates a
general error status. Use the following table to interpret device status
using the LED light.
User LED light patterns
Light status Interpretation
Green solid The device is operating normally.
Green blinking The device is in Service Mode.
Amber blinking The device has a paper jam, a staple jam, or an operation error.
Or, the device is detached from the printer.
Amber solid The device has a malfunction.
Off The device is off.