Firewall pass through wires locations

[Rock Taxi]

I am trying to locate the pass through wires on the 2020 model under the hood and in the cab, and googling only shows me 2019 and earlier. It doesn't appear to be the same layout as far as I can tell. Does anyone know where the 4 pass through wires are on the 2020's (and if they even exist as I can't find mention of it in the manual)?

Ed

 

[Rock Taxi]

Still can't see them in the engine bay....

 

[Kopfjaeger]

I’ve looked quite a bit in mine as well, found the upfitter switches just fine, but not the pass-thru. I’ve looked where it says in the layout book, but my only guess is that the wires are taped in the bundle going into the ECM. If I get brave and pull it all apart and find them I’ll take a picture.

 

[Rock Taxi]

Has anyone found the pass-through wires yet (both under the hood and behind the kick panel)? I really need one upfitter switch to come back into the cab to power the in-cab winch controller I am building. I just hate poking new holes in stuff on the firewall when Ford supposedly did me a solid and gave me wires.

Ed

 

[Kopfjaeger]

Behind the kick plate just to the left of the green tag in the attached picture you will see the bundle.


It’s a terrible design, you have about 2-3 inches of wire to work with in the top corner. I have looked everywhere under the hood, I know they must be wrapped up in a bundle of wires somewhere, but I don’t want to blindly unwrap all of them.

Has anyone found the pass-through wires yet (both under the hood and behind the kick panel)? I really need one upfitter switch to come back into the cab to power the in-cab winch controller I am building. I just hate poking new holes in stuff on the firewall when Ford supposedly did me a solid and gave me wires.

Ed

 

[bbrett]

Did you have any luck finding the ones under the hood?

 

[davidb1841]

I am trying to locate the pass through wires on the 2020 model under the hood and in the cab, and googling only shows me 2019 and earlier. It doesn't appear to be the same layout as far as I can tell. Does anyone know where the 4 pass through wires are on the 2020's (and if they even exist as I can't find mention of it in the manual)?

Ed

I heard they are almost impossible to use cause they are so short. also there is a hole on the flat part of the passenger foot well-- where there right foot big toe might be-- with a rubber gromet......very easy way to connect cab and engine bay. (driver side also)

 

[Iron Man]

I am trying to locate the pass through wires on the 2020 model under the hood and in the cab, and googling only shows me 2019 and earlier. It doesn't appear to be the same layout as far as I can tell. Does anyone know where the 4 pass through wires are on the 2020's (and if they even exist as I can't find mention of it in the manual)?

Ed

I sent out a question earlier to you about the difference between a 250 Tremor and a 350 Tremor with towing, and 5th wheeling capacity, and i guess also payload. If it was just a sticker in the door jam thats the only difference and absolutely nothing else.
I only asked you because I was under the impression you along with a couple of other Members of this site were very Knowledgable of trucks and were so helpful with a green Super Duty future owner like myself.
If you can also add some insight add greatly appreiate it Rock Taxi.
You are as far as I know a go ask dude on my list of getting the best answer possible. Thanks, Don (aka) Iron Man

 

[bbrett]

Found this... I'm going to investigate tomorrow.

also, check out this post.
https://www.ford-trucks.com/forums/1606739-2020-upfitter-switch-wiring-2.html#post19155795

if you scroll through, you'll find more pictures and experiences..

 

[Jipoxy]

Hello all. I'm late on the thread but wanted to share my experience with this. I ended up using a bore scope to find these darn wires. Attachment is a picture of the under the hood side of things (which are the harder ones to find once you know what colour codes to look for). On my truck all 4 wires shared one blunt end and were lightly taped down. Still though, what a pain to still have to reach under there to connect wiring to...inside the cab (passenger side) the wires were pretty much flush against the side wall with an "ample" 1.5" of wire to work with your fingertips with.

Hope this helps!

 

[timf343]

Wow, thanks for that photo. I guess we shouldn't complain since the wires being there at all do eliminate the need for cutting a new hole thru the firewall, but man, a pair of $5 terminal blocks mounted on either end of those wires would have been a really nice touch.

Anyway, I'm going to use something like these to extend the wires, anyone have experience...will they hold up to under hood heat and dirt?

Larlansz 125 Solderless Quick Splice Snap Wire Connector, 50 pcs red 22 Through 18 Gauge,50 pcs Blue 16 Through 14 Gauge,25 pcs Yellow 12 Through 10 Gauge: Amazon.com: Industrial & Scientific

Larlansz 125 Solderless Quick Splice Snap Wire Connector, 50 pcs red 22 Through 18 Gauge,50 pcs Blue 16 Through 14 Gauge,25 pcs Yellow 12 Through 10 Gauge: Amazon.com: Industrial & Scientific

smile.amazon.com

There is no way I'll fit my hand into that tight of a spot and still have the dexterity to reliably and confidently splice the right wires, so this looks like a job for my nephews. But once extended, the wires will be way more usable/useful.

 

[strogg]

I just want to share my experience. After finding where the pass through wires were in the cabin and the fender well, I decided it was easier to drill a new hole and install a grommet to pass all new wires through. Since the firewall is aluminum, a stepper bit drilled through it like butter.

 

[Frp tremor]

Hey guys, I have a 2021 Ford F250 Tremor the pass through wires in my truck were located in the engine bay by the upfitter switch wires.

I discovered this after tearing the whole wheel well apart and tearing all of the wiring apart in the wheel well. ?

Ford really needs to give better instructions on where these wires are located LOL.

Please see all my photos.

 

[ccw]

Hey guys, I have a 2021 Ford F250 Tremor the pass through wires in my truck were located in the engine bay by the upfitter switch wires.

I discovered this after tearing the whole wheel well apart and tearing all of the wiring apart in the wheel well. ?

Ford really needs to give better instructions on where these wires are located LOL.

Please see all my photos. View attachment 26043View attachment 26044View attachment 26045View attachment 26046View attachment 26047

Ya I guess the instructions from Ford are pretty thorough about the wiring diagrams, but not so much the physical location of the wires.

Might be too late for you, but for anyone else reading this thread here’s the official document on the upfitter switches from Ford: https://www.ford-trucks.com/forums/attachment.php?attachmentid=268186&d=1591478849

 

[Frp tremor]

Ya I guess the instructions from Ford are pretty thorough about the wiring diagrams, but not so much the physical location of the wires.

Might be too late for you, but for anyone else reading this thread here’s the official document on the upfitter switches from Ford: https://www.ford-trucks.com/forums/attachment.php?attachmentid=268186&d=1591478849

That diagram is good. But my upfitter relay box is on the passenger side not the driver side.

 

[ibeb]

Hey guys, I have a 2021 Ford F250 Tremor the pass through wires in my truck were located in the engine bay by the upfitter switch wires.

I discovered this after tearing the whole wheel well apart and tearing all of the wiring apart in the wheel well. ?

Ford really needs to give better instructions on where these wires are located LOL.

Please see all my photos. View attachment 26043View attachment 26044View attachment 26045View attachment 26046View attachment 26047

Are the engine bay side pass through wires on your truck really that long? I found mine under there, but no way in hell they will make it up that high for what should be an easy connection to the upfitter switches.

The in-cab wires are short, but workable. The engine side ones are a joke without removing the wheel well liner.

Erik

 

[Frp tremor]

Are the engine bay side pass through wires on your truck really that long? I found mine under there, but no way in hell they will make it up that high for what should be an easy connection to the upfitter switches.

The in-cab wires are short, but workable. The engine side ones are a joke without removing the wheel well liner.

Erik

Yeah the pass through wires on my 2021 tremor are very long witch is crazy.

I just wired up some lights on my dad's 2020 F350 and the pass through wires we're almost impossible to use because they were so short.

The pass through wires on my 2021 tremor we're left really long in the engine bay and left really long under the dash also.

I just got my truck about 2 or 3 weeks ago so I don't know if ford is maybe changing the newer trucks to have more wire, but there was much more wire then on my dad's 2020 f350.

What's funny is that my buddy has a Raptor and he came over and asked what I was doing so I told him and then he pointed out where the wires might be in the engine bay and I told him no they are in the wheel well, witch is where they where on my dad's 2020 f350.

So while I was still digging in the wire harness in the wheel well my raptor buddy was like I found them! He told me they are in the same spot under the hood as his 2020 raptor.

 

[ibeb]

Yeah the pass through wires on my 2021 tremor are very long witch is crazy.

I just wired up some lights on my dad's 2020 F350 and the pass through wires we're almost impossible to use because they were so short.

The pass through wires on my 2021 tremor we're left really long in the engine bay and left really long under the dash also.

I just got my truck about 2 or 3 weeks ago so I don't know if ford is maybe changing the newer trucks to have more wire, but there was much more wire then on my dad's 2020 f350.

What's funny is that my buddy has a Raptor and he came over and asked what I was doing so I told him and then he pointed out where the wires might be in the engine bay and I told him no they are in the wheel well, witch is where they where on my dad's 2020 f350.

So while I was still digging in the wire harness in the wheel well my raptor buddy was like I found them! He told me they are in the same spot under the hood as his 2020 raptor.

Thanks. I used my phone to video where they were supposed to be, saw them, can get a hold of them but that is about it without digging in. I was going to use the power for my mirror spot light mod so that it wasn't constant hot, but decided to just tap into the constant wire at the module - I just have to make sure they aren't left on.

Erik

 

[Frp tremor]

Thanks. I used my phone to video where they were supposed to be, saw them, can get a hold of them but that is about it without digging in. I was going to use the power for my mirror spot light mod so that it wasn't constant hot, but decided to just tap into the constant wire at the module - I just have to make sure they aren't left on.

Erik

No worries, ya the short wires are very frustrating.? lol ya definitely don't want a dead truck.

 

[Fencelizard]

I just want to share my experience. After finding where the pass through wires were in the cabin and the fender well, I decided it was easier to drill a new hole and install a grommet to pass all new wires through. Since the firewall is aluminum, a stepper bit drilled through it like butter.

Can you tell me/pictures of the spot you drilled to pass wires through the firewall? I have a 2020 with ridiculously short wires. TIA