Stevenew

MikeD134, nope, I haven't plugged in a trailer yet. I don't have one. But at the connector the hot pin is always hot, and when the lights are turned on two other pins show power.

I've seen a video where a guy uses a multimeter to check the different pins - but he doesn't say what year it is so it could be a much older truck.

For the truck to "see" a trailer surely means some connections across a few of the pins, right? Probably not a trailer brake controller, but at least running lights, turn signals, backup lights, brake lights.

Otherwise those test units wouldn't work. So that counts as "seeing" a trailer.

Thanks for that wiring diagram link. I found all six parts here: https://f01.justanswer.com/nmwagscha...towing_oem.pdf

I'm probably chasing my tail 10% of the time. Lol. Lots to learn.

Stevenew

Thanks for that link - although it didn't work directly, it led me here: https://www.etrailer.com/faq-wiring.aspx

At least the heavy duty / commercial wiring has round pins instead of blades! And I noticed the other two have everything in the same positions on the connector - only the wire colors are different. Still, this is going to be useful to me because the truck most likely had the "traditional" (utility/equipment/cargo trailer) whereas I'll be hooking up the "RV Standard" (5th wheel/travel trailer/camper).

So I should be able to figure out the wire colors now - thanks!

Stevenew

I started looking at 7 pin testers after your reply. I'm reading reviews on Amazon and it looks like the testers are all upside down for a Ford truck. You have any you would recommend?

henfield

I'm going to circle back to my earlier comment that I'm pretty convinced the PO redid the truck side of the 7 way to suit some trailer set up he has. At least as convinced as I can be as photos of that area is difficult.
I've towed several different 7 way trailers none have had any problems with the way the truck is wired from factory.
This problem isn't going to be fixed until you or a shop takes that plug apart.

J Pesons

If I understand this thread, with the newer style pickups only the Ford controller will work for connecting a trailer to the vehicle, and the connector must be paired via forscan or the dealer, is this correct?

MikeD134

No, you can use an aftermarket one, but you don't get the integration with the truck like you do with the Ford OEM. for example, trailer brake control when the ABS unit kicks in.

tfalk

Just a data point, those testers with the led lights are not always 100% reliable. I just spent several days chasing a problem on my 18 F350 where the trailer running lights wouldn't work. I connected 2 other tow vehicles and the running lights on the trailer worked so I knew it was the truck and not the trailer. I bought one of the testers on amazon and it showed the running lights were OK. I checked the 7 pin with a voltmeter and I was only getting 3 volts on the running light pin. I pulled the fuse and it tested Ok for continuity. I replaced the fuse and now I have running lights and 12 volts at the 7 pin. Never saw that happen before, must be something with the fuse where it just wasn't getting full voltage across.