Trailer 7 way plug problem

[cpaharley2008]

and tell you if your plug is "live" when the motor/ignition is off.

[fudge_brownie]

My issues described above have subsided but new ones have appeared with time. I can now make a solid connection and all lights are working. However, as I travel it works loose from the socket and I lose trailer lighting and brakes. Not good.

For now, I have resorted to Jim’s method and clamp an extra large reusable Zip Tie around the cord and the lid on the box. I do not use the nifty storage socket that I have seen on Jim’s trailer. Jim you have finally had one more than a year, do you still like it?

It appears these cords have a limited lifespan. Waiting with baited breathe for your solution, Leon.

[gbaglo]

My Prodigy P2 shows 'NC' when not connected.

[fudge_brownie]

Would the brake controller show a trailer connected when “live”? My Prodigy at least indicates if it finds a trailer.

Originally Posted by cpaharley2008

and tell you if your plug is "live" when the motor/ignition is off.

[cpaharley2008]

Originally Posted by fudge_brownie

My issues described above have subsided but new ones have appeared with time. I can now make a solid connection and all lights are working. However, as I travel it works loose from the socket and I lose trailer lighting and brakes. Not good.

For now, I have resorted to Jim’s method and clamp an extra large reusable Zip Tie around the cord and the lid on the box. I do not use the nifty storage socket that I have seen on Jim’s trailer. Jim you have finally had one more than a year, do you still like it?

It appears these cords have a limited lifespan. Waiting with baited breathe for your solution, Leon.

I think this one is a keeper, a "new" classic....... BTW, those protectors come in variety of mounting, on the box or propane cover or now on the jack stand

[mtnest]

Keep an eye out for condensation. The inexpensive rubber plug protector I have traps condensation on its inside when covering the plug so I stopped using it. I figured it would hasten the contacts corroding. -Tom

[LeonW]

Originally Posted by gbaglo

My Prodigy P2 shows 'NC' when not connected.

I mine, the little "c" between two dots goes away but it near my knee and I don't always see it right away. I do use lights when towing, but in the sunlight, it is hard to see if the running lights are on.

[C&G in FL]

Originally Posted by mtnest

Keep an eye out for condensation. The inexpensive rubber plug protector I have traps condensation on its inside when covering the plug so I stopped using it. I figured it would hasten the contacts corroding. -Tom

Corrosion TYPICALLY occurs on DC circuit connectors most often on negative terminals. On the trailer’s plug, that would be the pin at 5:00 in relation to the key (small rectangular alignment projection). I have used rubber caps on trailer umbilicals for years with no corrosion problems. An occasional shot of electrical contact cleaner on the terminals is all that I use. Even if one doesn’t use a protective cap of some sort, cleaning the contacts periodically is a good practice. While the “cord holder” Jim has described as a “keeper” works well for bumper pull trailers, those (most) of us who have 5.0TAs coil the umbilical cord and store it in the rear of the pin box.

[rubicon327]

Originally Posted by fudge_brownie

Would the brake controller show a trailer connected when “live”? My Prodigy at least indicates if it finds a trailer.

Not sure exactly what you are asking but the Prodigy when connected is only proving you have a complete circuit on the blue brake wire and black ground wire. It is not telling you anything about whether the lights are working or not.

[DenverRTC]

Our 7-pin experiences:

Current equipment:
2015 GMC Sierra 2500HD Duramax with brake controller option
2019 E21

Previous equipment:
2004 GMC Sierra 2500HD Duramax with after market brake controller
2009 Acura MDX with after market brake controller
2013 E19

For anyone wondering why the 2500HD diesel, we just sold our 13,000 pound fifth wheel.

We had no known errors until replacing the 2004 Sierra with the 2015 Sierra.

When we were about 300 miles on our first trip from home pulling the E19 with the 2015 Sierra for the first time the “ding,ding,ding” began. Each error included the message “check trailer wiring”. Almost constant errors with each error followed by a “trailer connected” message. I would stop and reset the plug and it would be okay but only for a short while. It was extremely annoying.

Not being aware of the good info on this forum I took my own action. Not knowing the exact cause of the error I replaced the trailer connector wire with this one from Amazon and the errors totally went away.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

In October, 2019 we replaced the E19 with a new E21. We picked up our tailer and were about 400 miles south of Chilliwak and guess what, “ding,ding,ding”. But not as frequent as with the E19.

So I stopped at the first Home Depot and got a 3 foot long velcro strip (non-adhesive). Cut a proper length and wrapped it firmly around the connected plug and outlet cover. This solved about 95% of the “ding,ding,ding”.

I also notice in our travels that the trailer wire gets very stiff below 50f. This stiffness makes the error frequency worse even with the velcro wrapped. When the temp is above about 50f the errors are almost zero with the velcro wrapped.

So I subscribed to this 7-pin thread and came across the GMC bulletin about the Pollack connector. I have ordered a Pollack plug from Amazon as below. It will arrive in mid April. Not a Prime item. I will post my results after replacing the plug and giving it a good try. Hopefully this will work since we have the under trailer insulation and it will not be fun changing the coupler wire.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

One added note. When we picked up the E21 in October ETI provided a trailer coupler pin similar to one below available from Amazon) with the comment “we find this works best”. I didn’t realize the full meaning of that comment. They threaded the coupler wire through this pin. This helped reduce the error frequency but not so much when the temp was under 50f with the wire stiff as a crow bar.

https://www.amazon.com/Curt-Manufact...e%2C172&sr=1-5

[fudge_brownie]

Interesting observations about temperatures. Most of my issues were in February when taking the unit out of storage. It was well below 50.. I have read about the Pollack brand and look forward to your results.

[padlin]

The one in my truck bed disconnects now and then. I cleaned it up with a can of contact cleaner, which helped some but not completely. Reseating it when it happens does work, jiggling it around does not.

[casejh]

Months ago I would get the ding, ding, ding also. I put one wrap of electrical tape around the plug and stuck it back in, thinking I will figure out what to do next. But so far that has it 100% cured so I haven't tried anything else.

[John in Santa Cruz]

properly plugged in, the spring loaded lid on the 7 pin vehicle receptacle SHOULD latch against a notch on the 7 blade plug and firmly hold it in place. its always worked for me.

[Vermilye]

Originally Posted by John in Santa Cruz

properly plugged in, the spring loaded lid on the 7 pin vehicle receptacle SHOULD latch against a notch on the 7 blade plug and firmly hold it in place. its always worked for me.

The cable for my 7 pin is also very stiff & I sometimes get a "Trailer Disconnected" message from the F 150, ofter after hitting a bump. It is only a partial disconnection - the rear view camera, which is powered by the taillights stays on. In any case, I tried putting a small bungee cord around the plug/cover, and it made things worse. A shot of contact spray helped, and I haven't had the problem since.

[gbaglo]

I tried a zip-tie and it too made matters worse.

[cpaharley2008]

I found one of these on lying the ground, while pumping gas. Works like a charm....mine is in black though....I believe it is a hair tie back?

[thoer]

I've had good luck with a piece of double side velcro wrapped around the lid, holding it down onto the plug. I seems like the springs on the lids are frequently not made strong enough.

[citabria90]

Originally Posted by John in Santa Cruz

properly plugged in, the spring loaded lid on the 7 pin vehicle receptacle SHOULD latch against a notch on the 7 blade plug and firmly hold it in place. its always worked for me.

Exactly! Look for a protruding tab on the inside of the spring-loaded cover and make sure that it engages the plug. This will hold the plug firmly in place without any need for any rubber bands, tape, hair ties, etc.

Chuck

[ichrisdr]

I was the person who posted my solution on post #25. I sold my E19 last year and haven't read thru all the prior posts but one thing I will mention is if you are having the "ding" trailer not connected issue with a GMC you can duplicate the problem in the driveway by just manually moving the plug in the truck receiver.