Excellent photos! Did you do the install? Was the left grommet slot blank before the install?

Talk about meticulous if you have these photos from four years ago. This is great info, what this shows me is that your trailer harness goes through the left grommet hole, not the right one (where the PDC/CA harness goes through.) My problem is the left hole is already occupied with a pretty sizable harness that feeds through and then makes an immediate turn behind the heat shielding, never to be seen again. No clue what it is for. So you're kinda confirming that if you have PDC you can't use the right grommet hole unless you figure out some way to feed a PDC harness through the trailer grommet. That's getting into some surgery I'd like to avoid. I also thought of just drilling another grommet hole, but the space in that area is pretty restricted, it would be pretty kludgey.