Looking For 7-Way Wiring Harness For 2005 Ford F-350 Lariat

Updated 10/31/2025 | Published 10/07/2025

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 7-Way and 4-Pole Flat Connectors

(718)

$34.44

Question:

I have a 2005 F350 Lariat. It has a 6 pin round in the bumper and one it the bed. When looking to install a 7 pin flat for camper in the truck, i looked at the wiring harness under the bumper near the spare tire. The factory plug looks like nothing Ive seen before and cannot find a harness to fit it. It is a round plug and has 2 rows of 4 8 in total pin holes with a red strip in the middle between those 2 rows. I can picture if you tell me where to send. I need a wiring harness that goes from that to 6 pin flat. Every time I look only for the harness, it has the large round connectors. Please advise. Thank you in advance.

asked by: Barry

Expert Reply:

Hello Barry, thanks for reaching out. So all of the wiring we offer for the 2005 Ford F350 connects to the factory USCAR connector, or the large round connector you mentioned (pictured below).

Does your factory wiring not use a USCAR connector? It should be a simple matter of disconnecting the old one, and plugging in a new one with a 7-way like part # C55774.

There is no way to add pictures on here (yet), but you can email them to me if you wish. My email is [email protected]. I am happy to take a look but I can already tell you we likely would not have any thing to mate with the connector you mentioned.

expert reply by: Jesse M

Curt USCAR Connector
(click to enlarge)

Jesse M.

10/30/2025

Hey Barry, were you able to figure out whether your F350 uses the USCAR connector for that wiring harness? Knowing what you found could help others trying to add a 7-way and 4-flat setup to their trucks. Your update could make it easier for the next person with the same issue.

Barry

10/30/2025

@JesseM I did find out ( and have already mentioned it to you guys) that the previous owner of my truck actually changed the original wiring harness by cutting off the plug and wiring in a harness from a 1990 Ford truck. After searching high and low, I found the description of the plug he had changed it to.

Jesse M.

10/31/2025

@Barry Thanks for sharing! That actually explains a lot. Glad to hear you found the plug you needed. Feel free to come back anytime you need anything!