City Light Bulb Holder for H4 Lights

If you have H4 lights on your Vanagon or Eurovan, you may have a strange hole in the rear of the reflector that you can't fully understand.  This hole was made for a what was called a "city light" in Europe.  These lights would come on when you would turn your running lights on (the first click on your headlight switch).  In the USA these lights were not required and I am not really sure what their purpose is.  However if you have a hole in the back of your light housing, you really want to plug it to seal up the light.  These bases will allow you to do that.  If you want to put a bulb in it and have it light up, here is the part number for that bulb N0177172.  You are buying one of these, and one is required per light so two per van.