2007 Expedition trailer wiring

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jd-53e

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Just picked up an 07 XLT with the factory flat 4 wiring and plug under the bumper. There is a fifth, blue wire labeled "electric brake" that is taped to the harness and connected to nothing. The fuse and the relay are not in the fuse box, but that's not a problem. The standard square gray connector for the brake controller is under the dash just behind the OBD port. I converted my '93 F-150 and my '00 Expy with ease, but this 07 isn't like the others and none of the after-market kits have an '07 variant. Anyone coverted a flat 4 to 7-wire (to include electric brakes, 12v power, and back up lights)? I hate to break out the wire cutters and electrical tape so early in it's life...
 
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jd-53e

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Unfortunately, the '07 I bought did not have the 536 (HD towing) package; just the basic 4-wire. This deal was just too good to pass up despite it's 4-wire limitation.

BTW, the Arrow is awesome. What an outstanding, legendary effort!
 
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AvroAero

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I agree!

I can give ya a hand here, either you go to a dealer and pay fairly hefty for them to do it, or I can give ya some schematics for it and you go to work. Unfortunately theres just not enough to work with to make a 4 to a 7 pin. It's like trying to make a standalone turn signal. (on a trailer that is)
 

chevy24d

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JD - exactly the same problem for me too. I crawled under the truck and can't see where the wiring harness (4 wire harness w/brake controller wire) enters the floor board - if it even does.

Does anyone know how hard it would be to install the 7 pin harness?

In my scenario all I need is the 4 pin and a reverse light wire. Is there an easy way to get access to the reverse light wire?

Thanks,

Mark
 
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jd-53e

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Thanks AvroAero! If you have the schematics, I'd cetainly appreciate a copy! I'm not a big fan of others working on my vehicles and the more I look into this issue, the more I'm convinced this 4- to 7-wire conversion is going to require me running the necessary wires to the bumper.

I finally broke down and went to the parts department at the local Ford dealer. They claim the wiring harness is the same for both setups! Their computer lists only two wiring harnesses for the '07s; one for the regular frame and another for the extended. If someone else has an '07 Expedition with the 536 HD towing package, look under the hood at the left fender well. That's where the harness begins. If the label on the harness is visible, could you post the part number??? I'd like to compare that number against the one on my wiring harness.

Mark: I too traced the wiring looking for a place to tap for a back up light. The harness on my Expedition starts, as I mentioned above, under the hood at the left front fender. It runs back along the frame to the flat four plug on the bumper (there are a few stub out plugs along the way). There is no external wiring for the tail lights that I can find. If you need the reverse light to disable a surge brake for backing down the boat ramp, the existing blue brake controller wire may work. Check other posts, here and elsewhere.
 

chuck s

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No need to mess with the complete wiring harness that I can see. You can get a 7-pole Bargman kit at just about any RV dealer for maybe $25.

As you note, you already have 5 wires back there, including electric brakes (that blue wire). The other two wires are backup lights (center pole) and 12v "trailer battery charge." It's not worth rewiring the truck to get these as far as I'm concerned. Few trailers have backup lights and trailer battery charge is at most a trickle (under one amp) charge anyway.

I spent the extra $300 on the HD Trailer Tow option. Got the wiring and 9000 pounds maximum towing capacity, up from 6000.

NAJFS-IMG_0501.JPG


OTMTJ-67187576-IMG_0500.JPG


Tow relay/fuse box fully populated. Let me know if any other photos will help.

-- Chuck
 

Toddski

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Originally posted by chuck s
No need to mess with the complete wiring harness that I can see. You can get a 7-pole Bargman kit at just about any RV dealer for maybe $25.

As you note, you already have 5 wires back there, including electric brakes (that blue wire). The other two wires are backup lights (center pole) and 12v "trailer battery charge." It's not worth rewiring the truck to get these as far as I'm concerned. Few trailers have backup lights and trailer battery charge is at most a trickle (under one amp) charge anyway.

I spent the extra $300 on the HD Trailer Tow option. Got the wiring and 9000 pounds maximum towing capacity, up from 6000.

NAJFS-IMG_0501.JPG


OTMTJ-67187576-IMG_0500.JPG


Tow relay/fuse box fully populated. Let me know if any other photos will help.

-- Chuck

Good info Chuck.

I'm new to the forum. I just purchased a 2005 Expedition.
Are you the same Chuck S that owned a Jayco Kiwi?
 

chevy24d

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chuck - thanks for the pics. to my knoledge the four wires are probobly as follows;
left turn
right turn
running light
common

I don't think there is a reverse wire. I want this to activate my reverse lockout solenoid automatically.

I will double check the wires this weekend.

thanks

mark
 

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