Ok, I have a new KR F-350 equipped with the factory installed upfitter switches.
I would like to know just how you expect some one that is not 16 any more nor have hands the size of a pre-schooler to be able to access and work in the location that you chose to put the wiring under the hood???? Yes, I have located them; no, I can not get my old and large hands in there to even begin connect a wire to one of these!!!!!! Maybe your design engineers should voluntarily call every new owner to see if they can come out to their place of residence and assist in making electrical connections for said new owner! Ok....... Done ranting, otherwise love the truck

 

some have removed the wheel well liner on the drivers front to get better access.. I know the feeling.. I have huge hands too.. started using T Taps to make it easier.. no stripping, clamp the connector onto the wire (T) and then slide the new wire side male connector into the T socket.

under the dash is the killer for me.. just can't see it AND work on it

 

under the hood? my 2012 were under the dash.... but if I remember right the diagram had the color codes wrong... the colors for switch 1 was actually #4... couldn't figure out why the air compressor wouldn't turn on.. I started flipping all switches and discovered and double checked the diagram to confirm wiring issue....

 

he meant the passthru wires that come out behind the fuse box.

 

Only thing.....I dont like the t taps where there is ANY remote possibility of moisture/corrosion to take place! Personally, I prefer solder and heat shrink; but here, that seems to be out of the question!
Maybe some silicon filled butt connectors......
And dont want to try to use the under dash wires, beacuse I am trying to wire some strip LED's under the bed rails for some bed lighting when wanted! So then I would just have to run that thru the firewall someplace anyway.

 

How disappointing- I recall how difficult these were to use on my 2012, I was hoping that Ford had "fixed" this on the '15s. Apparently not - so I have this to look forward to when wiring up my up fitter switches. Argh!

 

You will have to connect the pass thru wires to the upfitter switch wires under the dash.

 

FORD definitely could have made these wires more accessible. It is a PITA to say the least. Long handled pliers and quick connectors is the only way I have found to conquer this problem.

 

So they also are not connected to the switches? WTF?anyone else remember the old commercial
"Ford has a better idea" ?????? LOLOLOLOL Haw Haw.....Not so much!

 

This is a duplicate.

 

These connections are not as bad as the ones under the hood.

 

No.. you don't HAVE to use the passthru wires.. they are provided as a convenience..(almost barely)

you could choose to create your OWN passthru wire, punch a hole thru one of the rubber grommets (under the carpet at the drivers foot, or in the back cab wall)..

I used the passthrus for my air compressor, aux fuel tank valve, and lately the light bar in the bumper... they were there, why not..

just to clarify,

the upfitter switches have wires that come out under the dash to the left of the steering column
the convenience firewall passthru wires come out in the same place under the dash, and behind the fuse box in the engine compartment.

 

I'll be under the dash today hooking lights up.

 

I also found that the upfitter switch wiring and the firewall pass through bundle are completely separate. When wiring my air compressor, I looked at the firewall pass through wire bundle and said to myself, "Self, fat chance!" I found an alternate route from the upfitter switch tails behind the fuse panel to the compressor. See page 114 of the owner's manual.

 

I did the same thing as you and even ran the undercarriage mounted compressor intake filter up through the grommet so it would stay dry up under the dash...