4 pin to 7 where is the 12V line?

[Kjhawkeye1]

Ok, here's more information about my story than you care to know, but it will give context to how I got to the point that I may be able to help. I have a 2010 ford expedition el xlt. It came with the 4 flat and hitch. I searched for quite some time to find out what the difference was between my version and the heavy duty tow package. I called numerous dealers who supposedly looked up my VIN and all that, but couldn't answer my question. Finally I learned that the only difference was a 7 pin, heavy duty radiator, and heavy duty transmission cooler. Adding these things would up my tow capacity by almost 3k pounds. My axle ratio was the same, just those three differences. I found the blue electric brake wire for a 7 pin capped just behind my 4 pin connector. Unfortunately on my vehicle it wasn't just plug and play because I couldn't find a 12v lead (which brings me to this post--and hopefully some help). I searched all over the web trying to figure out where it could be. I read that people just run one from the battery, but wanted to make this as clean and factory as possible. I stumbled across some posts and after some poking around with the information I had, I found that there is a 12v wire that goes into a wiring harness under the hood near the back driver side part of the engine compartment, but it doesn't come out the other side of the wiring harness...so basically it was run into a wiring harness, but not run out of it on the other end. I went down to the dealer, got the proper size pin and brought the wire out the other end, ran it in under the vehicle and wired it into a 7 pin. Maybe your year is stopped at a different spot, but that is where I found mine. If you decide you want to see a picture of the harness I'm talking about, let me know and I can take one and figure out a way to get it to you.

Any chance I can get in saving someone the headache I went through to figure something out, I'm happy to help.

I would be careful about towing over the capacity for what the truck is rated for from the factory on the door jamb. Not sure if an insurance company would cover an accident if you told them you could haul more just by upgrading a few parts on the vehicle even though you are correct in the differences. Just my two cents.

 

[cmc3]

I found the two missing wires were never installed in the harness. In my 2017 XLT they actually were were under the hood on drivers side.

 

[Jughead135]

I found that there is a 12v wire that goes into a wiring harness under the hood near the back driver side part of the engine compartment, but it doesn't come out the other side of the wiring harness...so basically it was run into a wiring harness, but not run out of it on the other end. I went down to the dealer, got the proper size pin and brought the wire out the other end, ran it in under the vehicle and wired it into a 7 pin. Maybe your year is stopped at a different spot, but that is where I found mine. If you decide you want to see a picture of the harness I'm talking about, let me know and I can take one and figure out a way to get it to you.

Any chance I can get in saving someone the headache I went through to figure something out, I'm happy to help.

Necropost, as I go through this same issue. I've ID'd the connector (see reference numbers tabulated below), but I cannot for the life of me find sourcing information for the pins. I've been reluctant to do the required surgery on the loom to get the connector disassembled until confirming I can source those pins. @bsevans5 , if you're still around, can you shed any light on this? Anyone else?

My best efforts at measuring these (connector apart, but not otherwise disassembled) shows flat blades of 2.8mm width for the male pins in question. I'd really like to avoid cutting the OEM wire upstream of the C139 connector, and it seems like pinning a couple of wires & joining into the connector that exists for the purpose should be easy & straightforward.... Ughhh!!!

Can anyone who's gone down this path already help figure this out? Thanks!



Various reference numbers (all apply to 2017 Ford Expedition XLT 3.5L with the "light duty" (i.e., 4-pin) factory towing; DYODD to determine how much, if any, is applicable to your model):
- Connector C139 on the 2017 Expi diagram; joins harnesses 12A581 (female sockets) on the upstream/forward end, & 14405 (male pins) on the downstream/rear end
- Ford p/n F3508A
- Pigtail Kit Part Number: WPT-1606; Service Part Number: KU2Z-14S411-SA (male/rear/downstream half)
- aftermarket p/n CET3403M (male/rear/downstream half of the connector; suffix "F" applies to the other half)
- Ford engineering drawing # F81A34
- connects to Harness 14405 (downstream / rear harness that runs to rear bumper carrying the various trailer wires & others); of note, this was the only part the Ford parts counter would acknowledge existing, and offered to sell it to me for the bargain price $1,200.... I declined.
- Power & reverse wires confirmed in place (along w/ associated fuses) on upstream side
- "Missing" downstream pins are #15, spec'd at 6awg (!!!), Orange, for circuit CAT14, +12V Trailer Tow Battery Charging; and #18, spec'd at 14awg, Grey-Brown, for circuit CAT16, Trailer Tow Backup Lamps

 

[bsevans5]

Necropost, as I go through this same issue. I've ID'd the connector (see reference numbers tabulated below), but I cannot for the life of me find sourcing information for the pins. I've been reluctant to do the required surgery on the loom to get the connector disassembled until confirming I can source those pins. @bsevans5 , if you're still around, can you shed any light on this? Anyone else?

My best efforts at measuring these (connector apart, but not otherwise disassembled) shows flat blades of 2.8mm width for the male pins in question. I'd really like to avoid cutting the OEM wire upstream of the C139 connector, and it seems like pinning a couple of wires & joining into the connector that exists for the purpose should be easy & straightforward.... Ughhh!!!

Can anyone who's gone down this path already help figure this out? Thanks!



Various reference numbers (all apply to 2017 Ford Expedition XLT 3.5L; DYODD to determine how much, if any, is applicable to your model):
- Connector C139 on the 2017 Expi diagram; joins harnesses 12A581 (female sockets) on the upstream/forward end, & 14405 (male pins) on the downstream/rear end
- Ford p/n F3508A
- Pigtail Kit Part Number: WPT-1606; Service Part Number: KU2Z-14S411-SA (male/rear/downstream half)
- aftermarket p/n CET3403M (male/rear/downstream half of the connector; suffix "F" applies to the other half)
- Ford engineering drawing # F81A34
- connects to Harness 14405 (downstream / rear harness that runs to rear bumper carrying the various trailer wires & others); of note, this was the only part the Ford parts counter would acknowledge existing, and offered to sell it to me for the bargain price $1,200.... I declined.
- Power & reverse wires confirmed in place (along w/ associated fuses) on upstream side
- "Missing" downstream pins are #15, spec'd at 6awg (!!!), Orange, for circuit CAT14, +12V Trailer Tow Battery Charging; and #18, spec'd at 14awg, Grey-Brown, for circuit CAT16, Trailer Tow Backup Lamps

I didnt pull my wire harness apart. I found where the wire was run into a connector but didnt have a wire coming out on the other side of the connector and just ran a separate wire all the way to the back

 

[Jughead135]

I didnt pull my wire harness apart. I found where the wire was run into a connector but didnt have a wire coming out on the other side of the connector and just ran a separate wire all the way to the back

I'm not following--you said you got the appropriate pin from your local dealer (who is apparently much friendlier than mine!). What did you pin into? Where is the forward end of your new wire tapped in?

In my ideal world, I'd like to find the appropriate pins for #15 & #18 of C139, attach to my new wires, and run back to the rear bumper along w/ the existing bundle. Is that not what you did?

Thanks for the reply! Didn't know if you'd still be here this many years later!

 

[bsevans5]

I'm not following--you said you got the appropriate pin from your local dealer (who is apparently much friendlier than mine!). What did you pin into? Where is the forward end of your new wire tapped in?

In my ideal world, I'd like to find the appropriate pins for #15 & #18 of C139, attach to my new wires, and run back to the rear bumper along w/ the existing bundle. Is that not what you did?

Thanks for the reply! Didn't know if you'd still be here this many years later!

Im here. Fortunately the site notified me or I probably wouldn't have seen it. If you want to DM me your info I can connect with you directly. That may make it easier to answer questions

 

[Jughead135]

Im here. Fortunately the site notified me or I probably wouldn't have seen it. If you want to DM me your info I can connect with you directly. That may make it easier to answer questions

DM sent, thanks!