66gmc truck headlight wiring harnEss

Am putting a 66gmc basket case together on the headlight harness there is green and tan wires that go to the bulb plugs but there is also a extra green with a spade clip on it has to be hot when lights are on what does it go to

 

Parking lights?

 

these trucks had alot of optional things, so it could honestly just be an extra. ive had to go through wiring in a 66 c10 and there were afew extra connections even with everything working, so check to make sure everything is in working order and if it is just leave it

marker lights were an option on super late 66's