Parking light, marker light wiring help

[gran coupe john]

I don't know why the marker light and parking light won't work unless they are plugged in opposite way?

 

[72RoadRunnerGTX]

Looks to be reversed, there is a reason the molded connectors are color coded, match the yellow connectors.

 

[gran coupe john]

Yes, they don't work when matched. See they work when mismatched. Not sure why??

 

[72RoadRunnerGTX]

I see, the turn signal housing needs to be grounded to work correctly. Also make sure the forward lighting harness ground is connected at the core support near the battery.

 

[gran coupe john]

I know, I have it grounded at core support. Do they need mounted to the fender, and valance to be grounded?

 

[72RoadRunnerGTX]

Typically the turn signal housing depends on grounding through its mounting screws into the valance. Wiring diagram indicates an added ground wire (L9D-16BK), not seeing a third wire in your pics. Should be able to touch housing to the body somewhere to test.

 

[gran coupe john]

(L9D-16BK) is grounded. Will try grounding the housings tomorrow to see if that works.
Thank you