Okay, here's a shot of the 88 F150 I'm working on today. Lucky the battery is out, gives a better view.
Pic shot from top of fan blade pointing to passenger side. I highlighted the two ground pigtails come off the main ground.
I'm not positive on this, but they may have only had one pigtail in '86. And that would be the one that bolts to the fender well at about 12:00. Later years, like this one, they had the second ground that was dedicated to PCM and powertrain controls that looped down into the main harness, right there about 9:00.
These have been redone with soldered fasteners and heat shrink tubing. I suspect all of these vintages have been redone. The older pigtails had a connector that was notorious for green fuzzy buildup on the terminals that, if left untended, would build up enough resistance to cause all kinds of drivability grief.
Hope this helps.