Replacement Trailer Wiring Harness on a 2004 Ford F-150

Question

Question:

I have a 2004 f150 lariat and am trying to find a replacement trailer wiring harness. Everything I find has two round connectors to the vehicle and mine has a round and a rectangle connector.

asked by: Terry S

0

Expert Reply:

I would be happy to help you. For your 2004 Ford F-150 you're going to need the Tow Package Vehicle Wiring Harness with 7-Way Trailer Connector item # 118247. This harness has the rectangle connector that plugs directly into the factory harness.

I have linked an installation video below.

expert reply by: Jerred H

0

Answer 1

If you've tested the 7-way on the vehicle, and have determined that you have no signal on the left turn signal pin, closely examine the trailer connector. Make sure it's not damaged or excessively corroded and clean/replace if necessary. If…

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Answer 2

Hey Denzil! I have two possible options for you. If you think it is just your factory connector that's bad you can replace what you have with the 7- and 4-Pole Trailer Connector Socket #HM40975. However, if you want to go this route I would test…

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Answer 3

The only pin that should be continuously showing 12V power on the 7-Way connector on your vehicle is the 12V power circuit which is normally the black wire but not always. In 7-way wiring the 12V auxiliary power feed is carried on the contact at the…

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Answer 4

To get the 7-way and 4-way combined connector you will need to use the Curt T-Connector Vehicle Wiring Harness #C55242 to replace the factory harness and then you will be able to use the 7- and 4-Pole Trailer Connector Socket #HM40975. This connector…

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Answer 5

This sounds like a ground problem on the right side. The turn signal not working makes sense because with the brake lights, there is a constant signal coming through which is enough to make the lights illuminate on both sides like they should. But…

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Answer 6

The wiring of the Optronics Trailer Light #STL79RB that you listed are: The white wire, with the mounting eye, is a ground wire that needs to be connected to the white wire of your trailer wiring. The black wire would be connected to your running…

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Answer 7

The most likely cause for the turn signals not to work when the running lights are on with your trailer is a bad or weak ground. It's very possible that a weak ground connection can be just strong enough to allow sufficient current for some…

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Answer 8

The correct 7-way kit for your 2018 Ford F-150 that matches the rectangular connectors you sent us a picture of is the Curt part #C56413. I attached a picture our installers took that shows this connecting to same connectors.

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Answer 9

I would recommend the Hopkins 4 and 7-way part #HM40975. This harness comes with both a 7-way and a 4-way and comes with a mounting bracket to install it as well. Check out the install video I attached as well that shows it being installed on a…

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Answer 10

You will want to test the wiring you have found under your van to see if it is active. You will want to use a circuit tester like the part #PTW2993 to check the ports for voltage as you apply the different turn signal functions. If it is active then…

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Answer 11

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

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Answer 12

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Replacement Trailer Wiring Harness on a 2004 Ford F-150

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