Home Forums Truck Camper Adventure Forum Understanding the 7 pin trailer connector

Viewing 6 reply threads
  • Author
    Posts
    • #46583
      Kyle Banerjee
      Participant

      When attaching the trailer plug to my cabover, the trickle charge through the 7 pin connector didn’t seem to be working correctly. So I pulled out a multimeter and did not get the readings I expected.

      Viewed from my perspective (i.e. looking at the truck from the rear), I seem to get ground at the 1 o’clock position and positive at 5. Right turn signal is 9 oclock and left is 3. In other words, some stuff is opposite what I would expect. Testing from the truck camper side that was plugging in, I was getting positive and ground where expected.

      This 7 pin connector is part of a factory tow package, and I assume everything is done with harnesses that make it virtually impossible for them to get it wrong. Given that I don’t know anything about this stuff beyond what I learned in a couple internet searches, I wanted to get a reality check before taking it in. Am I out of my mind, or is it possible my factory trailer plug is wired incorrectly?

    • #46593
      ardvark
      Participant

      When you are plugged into your truck with the engine running, what voltage are you seeing at your battery/ies?

      Steve

      Steve and Andra
      2012 F350 6.2 gasser SRW LB
      Fab Fours front and rear in case we run into a rhino
      2019 Northstar Laredo SC

    • #46594
      Kyle Banerjee
      Participant

      Battery voltage is good — and it’s also good at all the pins *except* the one that goes to the positive terminal in the battery.

      After doing some poking around, I’ve discovered that standard installation for my connector is “upside down” explaining the weird pin behavior — but that my power problem is real and most likely because “smart connector” isn’t sensing a trailer and won’t send voltage down that line unless it senses brakes. I’ve found a number of guys griping on other forums about that.

      I have to get some warranty work done anyway, so I’ll ask at Ford if they can do anything about that. If they can’t, I can redirect the running lights wire which delivers 12V to the battery. I’d lose the gems and need to run my lights, but I’m not sure if I care. I’d much rather be able to override the annoying behavior.

      Another option is simply to route a wire from the positive terminal of the battery. Not sure if that would risk killing the battery when parked if I left the connector plugged in.

    • #46595
      ardvark
      Participant

      Kyle,

      Got it. Didn’t follow your initial post. This wiring diagram may help as all the brake circuit is looking for is resistance carrying a very small current. Traditional folks have wired in a “fooler” or a brake magnet into the circuit that would normally feed trailer brakes. The magnets are readily available and cheap. I have not tried it on the newest Ford trucks, but it has worked in the past. All it takes is a single magnet.

      https://www.etrailer.com/faq-wiring.aspx

      No guarantee, but you are correct. This is a really common issue with Ford owners and I think an example of engineer overdesign! 🙂

      Good luck,

      Steve

      Steve and Andra
      2012 F350 6.2 gasser SRW LB
      Fab Fours front and rear in case we run into a rhino
      2019 Northstar Laredo SC

    • #46712
      Kyle Banerjee
      Participant

      That sounds like a simple solution. Just googling around, I found this: https://www.amazon.com/gp/product/B00FZTWVE4/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

      If I can just plug something in rather than figuring out exactly what I need to place inline to fool the sensor, that’s a win for me. If it works, I’ll report back but otherwise I’ll just splice in a fake load

    • #46873
      Jefe4x4
      Moderator

      This is exactly the 7-pin to 7-pin wiring adapter I used on my 2020 Ford F-350 gasser to Northstar hookup.
      It bypasses the truck’s lamp-out sensor and does not trigger any warnings or hyper flashing.
      It now works as advertised.
      jefe

      2020 Ford F-350 XLT FX4 4WD SRW SB SC 7.3L Godzilla Gas TorqShift 10R140 397 amps dual Alt dual batts Frnt Dana 60; Rr Dana M275 E-locker 4.30's 4580/4320/4066# payload 7243# curb wt. 11,300# GVWR 5-er prepped. 2020 Northstar Laredo SC, 12v compressor fridge, cassette, 320w Solar sub zero insulation.

    • #52323
      Kyle Banerjee
      Participant

      Just realized that I never reported back.

      I’ve been using that cheapo gizmo ever since I posted and it work great. Truck thinks a trailer is attached and I get plenty of charge. The only caveat is that rough roads can shake it loose enough to break the connection but no problems with anything falling out so far.

Viewing 6 reply threads
  • You must be logged in to reply to this topic.