7-pin plug compatibility

[Paulx]

Hello, first post here.

I am kinda scratching my head over these plugs. They seem to be almost compatible, but not quite. Are all the blade type 7-pin connectors supposed to be compatible, or is there some matrix somewhere showing what works with what?

My trailer is a 2014 Salem 18'; it has a connector with blades split in the middle (that is, the pins are female), but the center is round. It says "Bargman". The truck is a 2014 Ram 1500 that has a connector already installed with blades that are folded. It says "Delphi" on the side. They don't seem to connect properly. Am I supposed to push harder, or what? Just by looking, it seems the folded blades of the Delphi are too thick to fit the split opening of the Bargman blades.

[beemerphile1]

Paulx wrote:
...Bargman or Pollak seems the most common.

In fact Bargman is a generic name for all seven pin connectors just like all facial tissues are called Kleenex.

[Paulx]

Thanks Old-Biscuit. It's always good to learn one is not going insane. 🙂

I have been on etrailer a lot, still couldn't find this info. I wish the manufacturers took care of their customers better by conforming to a standard. Thumbs down on Ram on this one, since Bargman or Pollak seems the most common.

[RoyB]

You can get great info on these trailer components from ETRAILER.COM... They also have alot of movies on how to install things...

Lots of good info on this site...

Roy Ken

[Old-Biscuit]

Paulx wrote:
Uh, that was not my question. I know where the wires go; I need to know the connector compatibility. Does every 7-pin blade type connector work with every other, or not?

NO they are NOT all compatible as you are finding out.

The 'Bargman' is pretty typical 7 pin plug used on trailer pigtails.
They make receptacles also.

'Pollak' is a typical 7 pin receptacle compatible with Bargman plugs.

Your Delphi is a good quality receptacle but the blades are thicker.
Being folded.....can you pinch them tighter so they are not as thick.

Shouldn't have to 'force' the plug into receptacle. Firm/solid push YES but not force......this is one area where a bigger hammer isn't the answer


The 12V power--top right (1 o'clock position on receptacle) is for 'charging' trailer battery.





Brakes---bottom right (5 o'clock position on receptacle) is what activates trailer brakes with truck brakes and brake controller.

On your RAM......think the 12V power is always hot. Unplug pigtail when using just trailer battery or you can drain truck battery also.

[Paulx]

Thanks, I will try to make these work together despite the 7-pin "standard" not being very standardized.

I'm also annoyed at the stiff, heavy cabling which torques the connectors. Seems as if these could have been designed better.

I have a Prodigy wireless brake controller. As far as I can tell the controller in the trailer frame uses the 12v wire on the tow vehicle 7-pin connector for brake power. I'm wondering if this power is isolated from the Ram 1500 battery. I suppose this power is passed through the brake controller as well as being used for brakes, to (for example) charge the trailer battery.

I wish I had a wiring diagram. It would make understanding this stuff so much easier.

[wa8yxm]

I have never seen a 7 pin trailer connector that did not fit in the socket I have somewhere... That said, I have seen some differences between the meaning of the odd wire.. More on that in a bit.

There are also 4, 5 and six pin connectors and those can be real fun.. About the only one I've seen that is 100% always the same is the flat 4

ON the 7 pins. There are the big 4 (RT/Stop, LT/Stop, Tail, Ground) there is the Brake lead, the Battery charge lead and that last "AUX" lead, sometimes used for backup lights, sometimes for other things.

And the Brake lead... Brake controllers and systems work differently.. MOST all trailers (I mean the kind without a motor in them) the controller provides power to the brakes.

But on the car I used to tow, the towed was the source of the power on that pin and taking it to ground applied the brakes... This one would only apply to motor homes with towed cars.

But when it comes to trailers... All the 7 pin plugs I've seen fit the sockets.

[calamus]

I have never seen a different one on any trailer I have ever hooked to make sure the plug is right side up and push till the catch on the lid hooks

[GordonThree]

Paulx wrote:
Uh, that was not my question. I know where the wires go; I need to know the connector compatibility. Does every 7-pin blade type connector work with every other, or not?

I don't know about EVERY 7-way, but the one used on your travel trailer and the one on your truck are compatible.

[GordonThree]

I think the female blades are "self cleaning", which really means, they're just spring loaded and need some elbow grease to force the mating connector in.

Put some dielectric grease in the female connector (trailer side), might make the mating easier.

[Paulx]

Uh, that was not my question. I know where the wires go; I need to know the connector compatibility. Does every 7-pin blade type connector work with every other, or not?

[westend]

Plug diagrams