Beachhead

This seems very strange, there is no notation of this in the instructions or on the official description for the accessory. Why would this wire be missing?

patrickoneal

Because XL? I honestly don't know, and it's really annoying that they left it out of the cab harness, yet they sell this kit without warning.

Here's a diagram of what's going on:

Edited to add: It's not clear in my picture, but we're connecting at the back side of C316, this is where the wire stops on my XL.

patrickoneal

Also, if you wouldn't mind, let us know if yours ends up being plug and play. The STX comes with some stuff the XL 101a doesn't AFAIK. Maybe you've got a more complete cab harness than the rest of us.

Beachhead

This is the backside of my headlight switch from under the dash. (I'm not sure how to get the dash down atm) It appears the blue-white wire is there. Are you saying this is missing on your trucks or am I off target?

If so, does this mean my truck is already wired for this?

Thanks,

patrickoneal

Nope, that wire will be there on all trucks, that's one of the ones I spliced into. It runs from the headlamp switch to the BCM. The missing wire is under the hood and it's not easy to see, you have to separate the 90 shroud from the connector to see the vacant slot in the connector. I have a pic of it in the first post, second picture(no white/blue wire in the fourth hole down). On the other side of the same connector there is a white/blue wire present on all trucks. I spliced it and ran a wire to the back of the headlamp switch.

That panel with the headlamp switch just folds down after pulling on both sides from the top. You might not need to bother if your STX is more completely wired than my XL 101a.

Edited: Made note of where the picture of the missing wire is.

Beachhead

Ok, I punched in my VIN to the internal ford wiring diagram site, and this is what I got for the headlight. I think I see the blue-white going from the BCM to the Headlamp switch. There's an odd symbol there though, i'm not sure what i'm looking at.

I wonder if your VIN would look differently than this?

patrickoneal

Mine probably looks exactly the same. If you press the cargo light button on your headlamp switch, it'll turn on the white cargo light on the exterior high mount brake light above your back glass. After you install the LED bed light kit, and program it, it will turn on the that same high mount cargo light as well as your new LEDs. The switch in the bed has the exact same function and, in fact, grounds the same pin on the BCM. If your truck is wired the same as mine, the wire from the bed switch just dead-ends under the hood and you'll have to add that jumper from under the hood to the headlamp switch to make it work.

Beachhead

Ok, if i'm following your photo correctly. Is the connector marked on my photo below C316? I'm not entirely sure since your picture shows what looks like carpet underneath and I have no such material under the hood on mine. Maybe a difference in engine? I have the 5.0.

I'd like to confirm if my truck is wired correctly or not before I get underneath and install the harness.

Thanks,

patrickoneal

That is C316. You most certainly have the white/blue wire in slot 31 of 34 on the side facing the driver. The other side is where it may be missing.

To look at it I did the following:

1. Disconnected the battery.
2. Carefully pried up the connectors, there's two christmas tree type retainers holding them down.
3. Lifted the bail to separate the two halves.
4. Carefully removed the black 90 degree cover from the male end to see the wires.

You may not have to pry up the clips like I did. I can't remember which side of the connector is fixed to the fender with the retainers.

patrickoneal

Mine is a 2017 3.5l Ecoboost, so it may be different, but I'd assume that all the lighting wiring would be identical. Since you seem to have access to wiring diagrams, try to find the pin out for connector C316. It might not show anything in regard to the LED bed lights, being that your VIN doesn't include them.