Recommended 5th Wheel to Gooseneck Wiring Adapter on 1999 Ford F-250 & 350 Super Duty w/Factory Plug

Published 08/24/2016

Products Featured in This Question

Hopkins Endurance 5th Wheel/Gooseneck 90-Degree Wiring Harness with 7-Pole Plug

(75)

$85.84

Ford Replacement OEM Tow Package Wiring Harness, 7-Way (Super Duty)

(422)

$69.72

Curt 5th Wheel/Gooseneck Custom Wiring Harness w/ 7-Pole Connector - 10' Long

(232)

$137.95

Question:

So is this setup something someone custom made? Both the plugs on the bumper and the one in the bed both come off of the same plug thats next to the frame I think i would like to upgrade to the 7way flat blade. Im just alittle confused. Cause everything makes it sound like the plug on the bumper should be separate from the one in the bed

asked by: Jacob S

Expert Reply:

Good news, I can help. Your year and model of Ford truck was made with two styles of connectors when they were being wired in at the factory. This means you will need to look at your factory 7-way under you vehicle and see if the back of the 7-way connector has the round adapter or if it has a molded cable that leads back to a rectangular connector on the drivers frame rail. I've attached an image of the two for you to better see.

If you have the factory round connector on the back of your 7-way you will need the 5th wheel to gooseneck wiring like the Curt # C56000.

Alternatively, if you have the rectangular connectors you will need the 5th wheel to gooseneck wiring harness like the Hopkins # HM40157, you were looking at. Both of these wiring harnesses will give you a 7-way round blade connector in the bed of your truck and retain the function of the 7-way round blade in the bumper of your vehicle.

The 7-way round blade connector is the most common and compatible style plug with towable items on the market. I have linked a Help Article on wiring for you to check out the functions that the 7 versus 6 way have. If your camper has a 6-pin round connector you may be interested in the # 47549 adapter this will adapt the 7-way to a 6-pin. It is important to note that the center pin of this adapter is set-up as the hot lead but can be changed if your center pin is wired as the brake.

I have linked all of the above-mentioned products to this page for your viewing and purchasing convenience.

expert reply by: Jackie C

click to enlarge

Jacob

8/24/2016

Jackie C.

8/24/2016

Thanks for you pictures they were helpful. Yes, it appears that your 6-pin was custom made. Let me try to explain this better for you. The your truck was equipped with the rectangle plugs (as seen in the images) this was one of two ways they made the truck. We now know that its the Hopkins harness # HM40157 you will need to have both connections for your truck. You will want to remove the 6-pin and plug in the # HM40157. Since your truck has the 6-pin on the bumper you will also need the # 118243 to regain the 7-way at the back of the vehicle. The connection the # HM40157 provides is what we call a T-harness. It takes the main connection (rectangular connectors) and then sends the signal and power to both plugs one located at the bumper of the vehicle and the other in the bed. You should find a second plug up in your frame for the # HM40157 to use, I think I can see it just behind in the image you sent. This will already have all the correct wires run from the front of the vehicle to power your 7-way plugs. You will plug the # 118243 into the # HM40157 and then the # HM40157 into your main vehicle wiring plug. I have linked all the above mentioned parts to this page for your purchasing convenience.