Grease Light The grease Light illuminates tough to reach areas where many grease zerks are located, enabling the technician to service vehicles much more quickly. The Grease Light also allows the technician to monitor the process to ensure that the grease fitting is not overfilled.. To use the Grease Light, simply connect the female end of the Grease Light fitting to the endo of your grease extension hose. Next, connect a grease coupler to the male end of the Grease Light fitting. 585 Yes -