Just for everyone’s info. I went to put a resistor in for high idle today so I took the wheel well liner off on the passenger side and couldn’t find the wires starting looking up YouTube videos and they all said they were right about the harness so I thought we’ll maybe they got taped in so I proceeded to take all the tape off the main harness never found the damn wires. Decided to take a break and look in the owners manual and I’ll be damn that they moved the location.. they are up by the upfitter switches toward the fire wall just to save everyone a few hours of work for nothing lol

 

Damn, sucks you had to find out that way. It has been posted on the forum that they are easier to access on the 2022's.

 

What are the pass through wires?

normally the upfitter wires are under the hood by the coolant reservoir.

so what are these other wires people always talk about?

also, get the BD Diesel Performance high idle switch. Super easy to install.

 

Pass through wires are the wires stubbed out through the firewall on the passenger side. Ford provides 4. It aids in getting power from the engine bay to devices inside the cab.

 

ahhh, ok. I wouldn’t ever use those so that’s why I don’t know. 🤷🏻‍♂️🤣

 

Inside the passenger footwell above the fuse panel. Firewall side is accessible either by removing the inner fender liner or by removing the passenger side battery.

 

Is that on a '22? From some of the posts I've read it sounded like nothing needs to be removed to access the engine side wires on the '22's.

 

On a 2022 nothing needs removed they are in the engine bay by the firewall close to the upfitter switches and they left a good amount inside the cab as well

 

the one from BD is over 100 bucks mine was 4 bucks for like 100 resistors I only use it to help warm up the 6.7 so no need to have it adjusted and even if I did I would splice another resistor before I spent that kind of money

 

My mistake for assuming nothing has changed on the pass thru wires for 22. Not like Ford to make things easier.

 

yea I spent like 3 hours looking for them lol take liners off untapped all kind of stuff lol just to find out I didn’t need to do anything

 

This would be correct, the pass through on the 2022 are taped to the side of another harness on the firewall next to the relay box, no need to remove anything to get to them.

I will add though that according to the manual the pass throughs were supposed to be marked with white mark tape, and the hot up fitter wire bundle marked with a red mark tape, mine were not marked with any color tape and I only found one bundle of wires in my search of the truck so i had no idea if they were the hot or pass through....... SO i had to untape them, heat gun off the cap they glued on them, fire up the truck, flip every switch, and put a meter on them and sure enough i got ZERO power out of any of them so it was obvious they were the pass through wires....

So the hunt started all over again to find the actual hot wires, myself and my son looked for a while and did not find any other set of wires that looked similar bundled or came to an end that you could hook to in the area of the relay box?? After digging around some more i finally got my hand under the relay box and could feel a mess of something under it, i released the tabs on the relay box so i could move out a bit and turn it some and discovered a giant bundle of something completely covered in entirety with black cloth tape about 3" long and 2" in diameter that came from out of the bottom of the relay box. Again, no white or red tape marks.... So it start unraveling all this taped up mess and sure enough another bundle of blunt end wires (8 of them maybe, more than 6 for sure) was discovered under all the tape and they were about 8" long once untaped, again no red mark or white mark tape under that. i have yet to test these wires since i had already put my heat gun and meter away before i found this bundle of wires since it was getting dark out but i have to assume these are indeed the hot wires to the upfitter switches.

 

So to add to my earlier post. pic of the relay box after its unclipped, you can see the hot upfitter wires coming out of it once they are untaped. The pass through wires are in the back ground with the white zip tie holding them back to the harness behind it, those were taped farther down on that harness from the factory.

Lasty, the wire colors in the book ARE WRONG compared to the actual hot wires coming out of the relay box, 10 wires are there, there is a tag on them that tells you what wire color goes to what switch in the cab, not one of them matched the owners manual. Also BE CAREFULL untaping that bundle of wires, the tag with the wire color info go torn in half when i untaped my wires from the bottom of the relay box....

 

Thank you for the clarification and photo.

 

Did you mean they are by the upfitter switch wiring? I was trying to imagine why the pass throughs would appear in my overhead console.