4 pin trailer elect plug to a 7 pin plug?

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Lou Schneider

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Mar 14, 2005
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12,402
You can usually find larger (tow vehicle) to smaller (trailer) adapters because the smaller connector just doesn't use some of the pins on the source plug. But not smaller to larger, for the same reason. Some of the circuits like trailer brakes won't be included on the smaller plug.
 

LarsMac

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Nov 15, 2015
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Yuma, CO
No, the RV doesnt have reverse light wires at the hitch only 4 wires, I need additional wires. So I am guessing I need to splice into the rv tailights to get the additional wires needed
Ouch. That is a bit of a pain.
 

phil-t

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Jul 10, 2017
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Ogdensburg, NY
Sounds like he might want to go the other way? Other thread about trailer requirements vs. what the RV has for wiring?
Yup, likely the light fixtures are the easiest access to the backup light wiring.
 

Panfish Pa

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Sep 23, 2018
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Cincinnati area
Some Trailer brake mfgrs. sell a wiring harness to hook up everything that is vehicle specific. This is Tekonsha's website, they do not make a wiring harness for an '04 Ford F450, but other brands might.
Yeah my rig is older like me. Thanks for looking it up, im sure me or my mechanic can rig something up seeing he also has a motorhome and familiar with them.
 

Old_Crow

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Nov 20, 2016
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Arkansas
Yeah my rig is older like me. Thanks for looking it up, im sure me or my mechanic can rig something up seeing he also has a motorhome and familiar with them.
When I wired my motor home for a 7 way, I bought this one that just plugged in to the existing 4 way. Then I only had to run the brake and charge wires. I didn't end up using the reverse lights as my trailer doesn't have them, but if I had, I would have just hooked up at one of the motor home taillights.
 

Panfish Pa

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Sep 23, 2018
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Cincinnati area
UPDATE: today I installed a 7 way plug on tope of the bumper and off center of the hitch, I used a L bracket and self tapping screws. I ended up being able to splice into one of the reverse lights on the coach, feed the wire through the wall and over the frame, it worked out well.
While I had my taillight assemblies apart I sanded them and painted them with a black gloss vinal paint, my 2004' is showing some greyness on the oem black plastics, and that gave it a perk up.
 
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