I pulled down the driver's side kick panel and found a few things I was looking for help on.

1) There is an unplugged gray connector that is clipped to the side of my OBDII port. It only has 4 pins, but it has a lot more wires going into it. It's hard to see but it has an OEM style clip that attaches it to the side if the OBDII port and the wires feed into the main cloth wire harness. It doesn't look like it was installed aftermarket (the harness doesn't have extra "bulk" to it and there isn't a visible exit point anywhere).

The part that raised an eyebrow though was what looks to be a rogue ground wire coming from the harness and tapped into the frame - this didn't look OEM to me.


2) There is a yellow wire that looks to be cut and tapped off at the end. At first I thought it could have been aftermarket because the previous owner had rear fog lights installed which were since removed (IE - the hole in the panel), but the wire seems to feed into the OEM harness and when I followed it, I couldn't find it exit point anywhere else and I doubt someone took the time to unwrap the entire harness and re-wrap it.

 

That 4-pin gray connector is C2122 and is a diagnostic test connector for HS3-CAN bus [High Speed ] and MS-CAN bus [Medium Speed].

I will dig deeper on your other questions. Might need to go out and look at my F150 to compare.

 

I believe 52merc is correct with respect to the connector. and. I think this diagram shows your taped off wire (related to snow plow option, usually not used)

 

Yes, the above is correct. My truck has the BK-GY wire ground as well, so everything is correct in OP's truck and the same as mine.

 

I'm a little surprised, but glad it's normal. Thanks for confirming guys!