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4-Pole Trailer Wiring Harness Options for 2012 Ford E350 Van


Looking for the right wiring harness for our E350 van.


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We can help you with a 4-pole flat trailer wiring harness for your 2012 Ford E-350 van. All types of wiring kits are shown on the linked page. These include products for vans equipped with no factory wiring, vans with a factory 4-pole set-up and vans with a factory 7-way. You can use the drop-down menu tool at the top of the page to Select Vehicle Style of your particular van to then see appropriate products.

If the van has no type of factory-installed trailer wiring you can use the plug-in T-Connector # C56020 from Curt for the lowest-cost option. This plugs in at your van taillights, no cutting or splicing required. This passive 4-pole harness taps into the existing vehicle wiring to get the lighting signals for the trailer. It does not have a powered converter as is found on Tekonsha harness # 118551, which uses a direct wired power connection to the van's battery to provide the actual power for the trailer lights.

This powered type of harness is generally preferred, and especially so if your trailer has a lot of lights since it can deliver higher output current to the trailer than the passive type. The T-One harness # 118551 can output up to 4.2-amps on each stop/turn circuit and up to 7.5-amps on the taillight circuit. The passive harness can pass only the same amount of power that can be carried by the vehicle wiring. If you have a trailer with many lights, and/or if they are all the incandescent type that requires more power than high-efficiency LED lights, or if you just want the van to be as safe and well-equipped as possible then you'll want to use this powered converter harness.

In addition to providing more power to the trailer lights, a powered converter will also serve to protect the van's own internal wiring from any potential faults or shorts in the trailer. With the passive harness # C56020 there is nothing to isolate the van from any wiring issues on the trailer. So, for example, if a dead short happened to occur somewhere in the trailer's wiring, that fault would likely blow a vehicle fuse and could potentially damage wiring in the van.

Installation of the Tekonsha harness is mostly a plug-in process at the van taillights, as with the passive harness, but it also has a single 12V power wire that will be run up to the engine compartment for connection to the battery + terminal using the included fuse holder. This one power wire is the only additional installation step required for a powered harness.

I have included for you both a helpful article on routing that one power wire and a video showing harness installation in a 2012 Ford van.

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